I believe that we will forever be oscillating in this space of winning and losing in the ground and air on alternate turns. Right now we're behind in the air and slightly ahead on the ground. But I don't believe that falling doubly behind in the air will still allow our troops to reach the fight unmolested, most likely we'll take some losses as our Skyrangers get shot down (as the aliens take losses from losing the air battle). So I'm voting for the fighter design.
But the TAV is also quite good this turn as a counter to their mimic-murder octopuses, which seem to be quite powerful. Furthermore I think it could have synergy with a revision for a 'sniper' unit class, using the TAV to reliably pick off disguised targets from range, as our railguns can penetrate cover and the mimic-murder octopuses seem limited to melee only.
Ultimately the better option depends on what the enemy picks. If they go for an air design, we should go for the Colibri to ensure we don't fall doubly behind, whereas if they go for a ground design we should go for the TAV, as the air is currently in a situation where we can still reach the fight safely and we want our ground combat to improve and meet theirs, hopefully resulting in the same situation as this turn's battle. However, absent that information, I'll err on the side of caution and vote for the Colibri. If the enemy goes for a ground design, we will then have switched sides and be winning in the air and losing on the ground.
Also, Happerry, I disagree with your opinion about using all three tokens on one design. In my view, we will never reach the point where we are guaranteed a stable supply of tokens. Us getting tokens depends on winning the fight, which in turn relies on whether we roll good designs, which is influenced by tokens. I think spending them on a single design is better than cautiously hoping for more tokens, which we are less likely to get without token-boosted designs.
Lightning Interceptor (1): Chiefwaffles
Tactical Awareness Visor (3): SaberToothTiger, Happerry, Blood_librarian
Colibri (2): strongpoint, Cnidaros
Final thoughts from re-reading the battle report: why did the aliens set down in the central plaza? Sounds like a terror mission where subtlety is ignored, but then the murder-mimic octopuses don't seem to be very effective as terror units, which shouldn't be disguised for more terror. Also, what's 'the gift'? Psionics? But the battle report doesn't mention any of our men getting subverted.
Also, this just makes the ground-air battle thing more confusing. As I read it, it seems like our two Ravens were defeated by two alien fighters, while three Phoenix-Skyrangers shot down the landing UFO for one loss. But then the remaining two Skyrangers were able to stay and provide close air support, whereas the alien fighters ... just buggered off back home without shooting down our Skyrangers? Unless they were too damaged to shoot down our Skyrangers, which seems unlikely, or ran out of ammo. This seems to indicate the ground and air battles are more disconnected than we believe, perhaps making the TAV a better option.
Seems like it may be worth a revision to reverse-engineer alien grenades if we're going to be doing more urban missions in future, which also gets us in to researching elerium explosives.