Ubergeek's Guide To Air Experimentals, Ranked By Unuselessness:CZAR. It's a T4 mercy whose primary weapon is it's massive discus it generates upon death, which should be hurled in the general direction of your enemy's largest concentration of pgens. It features a Crazy Zeropointmodulepowered Awesomium Reflexifior, which allows subspace displacement of the space-time continuum in order to bypass all known forms of shielding. Only requires enough air superiority to get it close enough to an enemy's base to activate it's primary weapon.
Bonus: it contains a laser beam which might occasionally be useful in theory (though highly unlikely), and a factory which you may safely ignore as if you are building a CZAR for an air factory, something is very wrong.
Frivolous and wholly useless "depth charges" (read: "empty toilet paper tubes") added at no extra charge.
Ahwassa.It's a bomber the size of a small city that that drops nukes. Enough said. Requires sufficient air superiority for it to vet and/or bomb an irreplaceable number of enemy engineers, the latter causing your enemy to exclaim "AHHHH! WASSA WAS THAT?!?!".
Multiple Ahwassas, or a combination of Ahwassa + other air bomber thingies, must be used to crack heavily shielded bases. One pass will usually down most shields, but they'll recharge before it can take another pass due to it's turning radius being marginally better than that of a boat car, requiring the aerial equivalent of the 50-point-turn to line up for another pass.
Also features enough AA to bat away small handfuls of ASF, and a death weapon comparable to that of the CZAR's main weapon but requiring leet aiming skills. (ie, divine intervention is required for it to hit anything useful)
Soul Ripper.The ugly stepchild of the above two. It's primary purpose is taking up an otherwise-potentially-useful experimental slot in the Cybran army.
Massed flak will shred it before it can touch a heavily defended base.
It has a mass donation service built into it's death weapon.
It's too slow for hit-and-run attacks.
It takes up resources that could be used for actually useful offensive units, such as massed ASF and T3 bombers, which are always a better value than the SR except for theoretical scenarios typically including a defending player with a single-digit IQ.
Because You Asked: Novax.The Novax is a mighty and feared weapon; the bane of noobs everywhere. "Novax" is actually it's codename; it's real name is: "Noob Obliteration Version Awesome X". It is banned from any game where true competition is required, as it can eventually kill massive simcity farms if you haven't built a single shield. En masse, they can eventually break through any shielded base, and are the most cost effective way for doing so, because games in which Novax's feature prominently typically involve air, teleporting SCUs, nukes, or anything else that might endanger one's massive simcity farm being safely disabled in the unit restrictions dialog to prevent unfair, cheap, lame, scrubby, and generally unfun games that might accidentally end before the 1hr mark.
In games where the participants' averaged IQ is higher than the temperature outside, the Novax is primarily used as a way to gloat, displaying that you have so far surpassed your enemy's production that you may freely invest in useless things solely for their highly prized "lulz" qualities.
The main weapon of the Novax is a bucket of water. A somewhat useful laser was originally planned, but due to budget cuts and highly unionized engineers in the UEF R&D department, it's current... "economical" alternative was used instead. Said engineers played a ton of Minecraft, however, so it evens out.
As a bonus, it contains a scouting beam which is roughly equivalent to a tiny penlight attached to an incredibly flimsy 20 foot stick weighted at both sides, which you are vainly attempting to shine in the general area that you want to see (while blindfolded and unsuccessfully attempting to counteract the symptoms of acute motion sickness). It typically takes upwards of 9000 seconds to eventually (and usually quite accidentally) sweep the area that you originally wanted to see.