The airdyne is great for shorter, really hard intervals. I’d stick to under 1/4 miles or 100-400 meters depending on how your bike measures distance.
Tabata’s: 20 seconds hard, 10 seconds easy by 8 X 2-4 sets with 1-3 minutes rest between sets
There are endless variations of these types of intervals but anything 30 seconds or less with a .5 to 2 rest ratio can work well. Keep your sets in the 2-5 minute range and repeat 2-5 times.