His air speed is still absolutely horrendous so his combo game is extremely limited.
Falco's air speed as you noted was always slow. It was slow in Melee, it was slow in Brawl, it was slow in Smash 4 even after the patch, and it's still slow in Ultimate.
It affects how he can combo, but with many of his moves launching at vertical or vertically diagonal angles, it's not that big of a deal. For example, Utilt and U-throw put his opponent above him, Dtilt puts his opponent up and in front of him and usually with a lot of hit stun because of how much damage and knockback it deals, Uair also puts his opponent above him and with his jump, he can quickly clear the distance between them for another follow-up if possible before the opponent drifts too far away from him, and Dair on grounded opponents pop them up for Falco similarly to Dtilt while on airborne opponents, they get spiked, Falco can possibly fast fall to reach them if they didn't get spiked to the lower blast zone. It's only really Nair, Fair, and D-throw that are outliers where Falco combos or strings horizontally.
Having good air speed would be nice, but given Falco's ability to combo and string things have been fine since Melee because of how his moves work together, it's not really necessary or that detrimental in my opinion. For neutral or disadvantage, however, yeah, his low air speed is an issue.
His up air in particular feels like it doesn't kill nearly as fast as it should. There's been instances where I've up aired a Mario at 140% off a double jump and did not get the kill.
This isn't anything new because of what happened to Uair in 1.0.8 Smash 4 and in Ultimate. Uair does 1 less damage, 9%, compared to Brawl and 1.0.8 Smash 4 Uair and 2 less damage than launch Smash 4 Uair. If it has the same or similar knockback values to 1.0.8 Smash Uair, then it's going to be even weaker.
Brawl and launch Smash 4 Uair had 27 base and 100 growth and a hit angle of 68 degrees on the leg hitboxes and 30 base and 20 growth and a hit angle of 80 degrees on the body hitbox which existed since Melee because reasons. 1.0.8 changed the knockback values to 35 base and 90 growth and the hit angles to 65, 75, and 85 degrees for all hitboxes. The scaling is much worse where at early percents, it does enough knockback that it's useful for comboing and stringing moves together, but at later percents, it just misses the mark where it can kill reliably, especially with the furthest hitbox having a slightly worse hit angle than before the patch. This is in addition to its damage reduction to Brawl's damage and Ultimate took it even further by dropping it to 9%.
Ultimate Uair's knockback is unknown at the moment, however, but it's either the same or similar enough that it's the crappy 1.0.8 Uair considering how it's been working.
I hate 1.0.8 Uair. The only problem with Falco's Uair prior to the patch was that it still had the silly body hitbox from Melee. It being frame 10 wasn't that bad, but Smash 4 Falco's pre-1.0.8 Uair was both a combo tool and a kill move and that was absolutely freaking awesome. I'm guessing they wanted it to be faster, well, then that's what they should have done. Drop it to frame 7 from frame 10, drop its damage to 10% if they felt like it was too powerful, but they shouldn't have messed with its knockback values. What they did was try to give a Captain Falcon, Mario, and ZSS-like Uair on a character who has slow horizontal movement overall and on a move that's not a backflip where it hits front then behind, but a frontflip where it hits behind then front. If it was frame 4 like Pikachu's, then sure, but it's frame 7 as of 1.0.8 and by the time it hits in front of him, it's around frame 10 or 11 which is still slower than Captain Falcon's and ZSS's frame 6 Uairs or Mario's frame 4 Uair.
Also because he jumps very high, shorthop aerials on small hit box characters are going to be unreliable at best and an easy punish at worst.
This is less of Falco's hop height problem and more of his hitboxes problem. According to this thread:
https://smashboards.com/threads/lan...ead-training-mode-tested-all-76-chars.464174/, Falco's hop height is only 0.1 higher than Fox's where Fox's jump height is 3.7 stage units, a little higher than Mario's, to Falco's 4.8 stage units. Greninja's jump is 4.0 stage units, but Greninja's hop is 2.0 to Falco's 1.9. I think it has to do something with jump force and other stuff that determines how high a character jumps since Falco is a fast-faller, but his jump is consistently the highest in the games he appears in and without buffs like Shulk's Jump Art.
Anyway, the only aerial Falco has that reliably hits low is Dair for obvious reasons. Nair, Fair, and Bair hit linearly in front of him and Uair covers above him. Fair at least his body is parallel to the ground and it has a landing hit, but that's still not comparable to having an move that actually hits below him because the move is aimed at hitting below the character, arcs low enough like Ike's Fair, or hits and lingers in a way like Link's, Mario's, or Wolf's Nairs.
Perhaps the best thing about him is that bair is still godly. It comes out fast and kills early.
Falco's Bair is frame 9 on startup now, the same as Fox's and like Wolf's, its startup was doubled from the previous game. Falco's Bair going from frame 4 to frame 9 and Wolf's going from frame 6 to frame 13. Their Bairs are still stupid given how hard they hit; clean Bair for Falco and sweet-spotted Bair for Wolf. Fox would probably kill Falco for his Bair, Smash 4 or Ultimate.
Out of a jump or a hop, it's roughly the same speed as his old Bair due to his jump being frame 3 now instead of frame 5 in Melee or frame 6 in Brawl and Smash 4. In the air, however, it's average in speed.
