General
As Terry's ground options are pretty good, opponents tend to jump a lot vs Terry, especially since aerials are so noncommittal in Ultimate. It is therefore very important to know how to hit your opponent out of the air.
You should get a good understanding on Terry's anti air options and their respective speed, range and risk/reward.
The same applies for your opponent's preferred options, so you can already react to the jump instead of waiting for the aerial option to come out. Otherwise you will find yourself too slow for intercepting your opponent and will likely get pressured or hit instead.
Visualising the range of Terry's common anti air options
Rising Tackle (RT)
RT is base Terry's most disjointed and far ranged anti air option. It's very good for catching your opponent trying to jump over you or trying to land on top of you with an aggressive option.
It does put you into free fall, so be careful not to get baited. However, it's landing lag is actually surprisingly low, so make good use of any nearby platform to land on.
Always use the command version, as it's better in any aspect when it comes to anti airing. Common charge setups include COIL and shield tilt down.
Also prefer the grounded version over the aerial one, as it has more iframes.
Neutral Air
Neutral Air is a fast option that covers the 45° angle in front of Terry. Its hitbox isn't very disjointed, so use the fast start up to intercept your opponent before their hitbox comes out. This can be especially effective if your opponent likes to space their aerials close to ground to make them more safe on shield.
Also make use of auto turnaround to cover cross ups.
Make sure to ready a special cancel in case you hit your opponent or their shield. Depending on your opponent's percent you could even get a grounded combo after fast falling.
Crack Shoot (CS)
Like Neutral Air, CS loses easily to hitboxes, especially horizontally. It makes up for this by covering a big arc very quickly and reliably due to many active frames.
Its relatively long start up requires you to time it either to their jump or the start of a far spacing attack. Trying to react with CS to a close to mid range attack will get you hit instead.
Using CS out of a full hop will allow you to disengage with a double jump if you whiff and catch opposing jumps better. It's best used as a preemptive callout since you spend quite some frames reaching the apex of your jump in addition to CS's startup.
Spot Dodge Attack (SDA)
Use SDA against opponent's trying to land on top of you.
The range isn't very impressive against spaced attacks, but the iframes allow you to literally go through short lasting hitboxes.
Keep in mind that your lower body will be vulnerable starting just before SDA's hitbox comes out. This is especially important against falling multi-hit moves.
Up Smash
Similar to SDA, but with a lot more kill power, Up Smash covers the area directly above Terry.
It doesn't have any iframes, but it will crouch from f1 until the hitbox comes out, allowing it to low profile moves like rising aerials in certain matchups.
Up smash also comes out fairly quickly out of shield and can be auto turned. It's not that laggy for a smash attack and can even be somewhat safe, in case your opponent manages to shield, due to its pushback.
Up Tilt
Same hitbox as SDA but with less iframes, making this almost always inferior to it.
The niche it has is a much faster start up and follow ups into PG or platform tech chases.
Power Geyser (PG)
It's a huge disjoint that also deals considerable damage and can and will kill, especially if your opponent isn't quick enough to change their DI from their aerial.
It is not without risk though, as it's not completely safe if shielded and the start up combined with the input will require you to read your opponent. You will need to be extremely aware of the spacing where your opponent cannot avoid it and their remaining movement options.
If mastered and used correctly though, it can be a very powerful tool to discourage your opponent from staying in the air.
Command Burning Knuckle (cBK)
cBK, the light version in particular, can be used in the air as a hard callout due to it's huge disjoint making it essentially a big, albeit slow and laggy, sword move.