In real life and in some other strategy games, aircraft are not a single uniform group that behaves similarly. There are multiple different subtypes with different properties. I think there are two of these subtypes that may be interesting for PA to incorporate. Planes have the potential to be INCREDIBLY useful compared to slower ground units, ships, etc. It is a dangerous possibility that air units' extreme mobility will allow them to be everywhere and always allowing all units to engage together, boiling the entire game down to a simple numbers game. All air unit design needs to be considered with avoiding this extremely undesirable possibility in mind. In general, aircraft should be the most expensive units available for how squishy they should be. Especially high-tech, advanced planes. Aircraft should not be large blobs of HP. Their survivability comes from their flight, their speed, and possibly stealth, not ability to absorb bullets. Do not repeat the abomination that was the AC-1000 in SupCom 2. The count of planes should be more significant than the durability of a plane- that way you hemorrhage resources as your air force takes casualties. Aircraft should be extremely powerful and mobile, and very vulnerable to anti-air. Battles involving air units should be highly lethal, and over quickly, to contrast with slower, more protracted ground battles. Air cavalry should be game-breakingly powerful when used expertly, and stupefyingly weak when used ineptly. Generally speaking, no smart player should EVER want to send a big wing of aircraft to fight a significant amount of anti-air in one place. Those planes can be more useful somewhere else- it's a big map. Preferably somewhere with less air defense. Scout to find where those planes would be best used, or do something clever to cripple the opponent's anti-air defense grid first. Fixed Wing Craft & Helicopters/Gunships Zero K does a reasonable job of creating a distinction between gunships and fixed wing craft. Fixed wing airplanes are much faster, and while they may be VTOL they generally must fly forward while aloft. Gunships (perhaps too specific a term) on the other hand are much slower, and have 360 degrees of freedom in flight. In Zero K, some anti-air is more effective against gunships, and some is more effective against fixed wing aircraft. Due to the slower speed of gunships, less accurate guns with higher DPS are more effective against gunships. Faster missile weapons, or your own fighters, are better against fixed wing craft, but other AA will act as a deterrent and do damage also. It is important to note that Zero K has no arbitrary damage types whatsoever- its counter relationships are 100% emergent, which is absolutely wonderfully elegant, and something PA should also try to create. I think that this distinction between hovering birds like helicopters and fixed wing planes is an excellent idea. However Zero K's exact implementation is most likely not the best way to do it in PA. Due to the large map size, movement speed of planes is going to be their most significant property. I suggest making fixed wing planes be VERY fast relative to other units. Sufficiently fast that their relative lack of maneuverability exposes them to a large land area whenever they are used. Even if they have exceptional maneuverability, a plane flying at Mach II making a U-turn is going to require quite a lot of space, potentially exposing them to a lot of anti-air fire. And after making a pass on a target, they will have to either break off or fly over and make another pass. Gunships (or other name for aircraft with helicopter-like properties) are not NEARLY so fast. This means they are much more useful for sustained operations in a small area, such as in close air support roles. Instead of screaming past the target and turning around like a fixed-wing craft, a gunship can just hover in place and fire away. Or even strafe a target while flying horizontally. However gunships are much slower, and as a result much less capable of extreme long-range operations. It takes gunships much more time to fly across an ocean and attack a target. Altitude To make air play more interesting, the aircraft "field" needs to be more than a flat, featureless plane. The most important way to add texture to the air board is to have features on the ground that interact strongly with air units. Ground units are slower, and the ground board contains static elements (structures) as well as terrain, making the ground game more positional and strategic. However I think more differentiation among air play itself is also a good idea. I think different altitude properties, in addition to different speed properties, will make aircraft a more dynamic battlefield. The best way to implement altitude simply would be to have three broad altitude categories rather than raw heights as distances. That is likely to be overly complex and micro-intensive. While technically many planes have wide altitude variation capabilities, in practice each one has a normal cruising altitude which will fall into one of the three categories- low, medium, and high. Planes should try to maintain their cruising altitude within their specified category. The actual range calculations should be done with the distances, however. So even a high altitude bomber might dip lower for some reason, and take fire from guns that normally can't reach it at its high cruising altitude. Medium altitude would be standard aircraft territory. Anti-air units check the target's distance against their range, and fire if able. All types of anti-air are able to attack targets at this altitude. Low Altitude Low altitude gives the aircraft the best access to the ground with its weapons, dropped units or pods, etc. However, it also gives ground-based AA the best access to the plane to shoot at it. Although not all types of AA might be able to fire at low altitude planes. SAM sites might have a sizable minimum range- so it might be unable to attack low flying air units. Not all planes are able to fly so low to the ground. Some planes might exclusively fly at this altitude, such as attack gunships. Any very fast planes which can be ordered to fly at low altitude should suffer a speed limitation while flying low. A simple, general rule might be that no unit can fly at supersonic speed at low altitude. I think multiple kinds of sensors are justified, and if we suppose the cheapest ground-based radar is used to detect air units at huge distances, then flying low could easily be made to make a plane radar-stealthed. So you need visual to shoot at it- but when you do, that plane is extremely likely to die immediately. Air patrols (or just a really dense picket line of AA) would defeat this vulnerability, but you might have a lot of land to patrol and a finite number of planes to do it. Low altitude flight also creates a special category of flying unit which might be used by skimmers, land units lifting off, jumpjet equipped bots, etc. Rather than treating a bot with jumpjets like a full-fledged air unit for just a moment, it creates a consistent treatment of low-altitude aircraft and ground units with limited flight capability. High Altitude High altitude is very high off the ground, making the plane very difficult to hit, but making any attacks against ground targets very inaccurate. Carpet bombing territory. Huge strategic bombers dropping hundreds of bombs at a time don't really care about being accurate against a specific target. Continuous bombing operations by a large wing of big, fat strat bombers would be fantastic against an enemy with a huge, sprawling complex where the bombs don't really have to hit anything in particular- drop 'em anywhere in the area, and they're going to hit something. Certain types of anti-air weapons cannot reach planes at this altitude, allowing high altitude craft to avoid most types of cheaper, shorter-range anti-air. This limits the amount of fire they take. High altitude planes would be most vulnerable to SAM's and enemy fighters. Provided you can maintain air superiority, a fleet of high-altitude planes can sustain air operations (with casualties over time) even over areas with lots of anti-air, where lower-flying craft would be completely annihilated. Analysis There are a few quite interesting emergent properties of creating these distinctions between aircraft categories. I'll just go down one possible strategic progression. For example, let's start with the possible player idea/principle that strategic bombers are really strong. If we start with this idea, it appears that because high-altitude craft are immune to most types of AA- say, flak or direct fire AA generally, that we want to build a lot of them. From the opponent's perspective- what counters a player making a lot of high-altitude bombers? The answer is that such bombers are more vulnerable to the type of anti-air the other player would prefer to have- SAM sites. SAM sites have huge range, and a widely spaced grid of them provides excellent, lethal air defense over a huge area, albeit at significant cost. And strategic bombers die in a single hit, and are bigger, more expensive, and fewer in number than other attack craft, such as a medium altitude bomber. However, a player might use low-altitude craft to take out SAM sites, thus enabling their high-altitude craft to operate in the area. This means an effective air defense is going to protect their expensive SAM sites with cheap, local, direct fire anti-air, to defend them against low-flying craft the SAM can't hit. These outposts would be widely spaced to maximize the effective range of the SAM sites, and minimize overkill. Which opens up the possibility of using ground units to neutralize a small anti-air outpost. A player might use low-altitude transport choppers (or some other method) to move ground units close to the base, landing outside the range of the direct-fire AA. There's all manner of interesting side-effects of creating a simple type differentiation between air units. A single universal "flying unit" has been tried many times, and has often resulted in extremely one-dimensional air play, which must be avoided. Conclusion This is just one possible concept for creating differentiation among air units. I propose two ways to differentiate flying units- fixed wing versus helicopter (or other name), and altitude differentiation. I think both would work well together.
Depending on UI implementation this could be very cool. But I it's probably not so wise to make low-altitude planes stealth - all transports/gunships/whatever falls into this category. Also, supersonic restriction for this category is not realistic either. Maybe you should create a very-low-altitude category for very specific crafts like WIGs (for stealthy transportation) or scout planes able to fly so low. To counter stealth, very-low-altitude crafts are to be attacked by ground units (it's something like 5-10 meters above the ground). As UI I imagine this implemented via four switches/buttons on commands panel for aircrafts. If aircraft can't move so low (probably only for very-low-altitude this restriction is realistic - every aircraft could move on low altitude. Well, except another category) or so high, than corresponding button is grayed out. "Normal" altitude is somehow highlighted and right-clicking on altitude bar sets altitude to normal. On strategic view one may differentiate different aircrafts via different icons/colors/glow. On non-strategic aircraft units may have differently colored glow around them, showing their current altitude (red-to-blue as low-to-high). Your idea may also be used for anti-orbital defense or air-launch orbital deploy (cheap flying orbital factory). You may restrict some "air units" (like shuttles) for high-altitude/orbital only. Heck, even orbital could be done via same mechanics.
We already know of at least one layer system. Low altitude is simple air craft. High altitude is for orbital stuff.
Idea is to add more layers without actually splitting plane types so much. So you may send your strat bombers on low altitude to hide from orbital defenses and then go back up just before enemy base. Isn't it cool?
only thing i can imagine is gunships and planes at the same "atmospherical" level of height, although gunships obviously needs to go lower than planes, but can just aswell get shot down by them, like in supcom. The second level would be orbital, where satellites and other orbital weaponry could be installed.
