Attack helicopters and this should be very wary:
[image: Sukhoi-Su-25-of-the-Russian-Air-Force-1090x500.jpg]
Service ceiling of 23,000 feet, max cruise of 513 knots. Analogous to the A-10 Warthog as far as mission profile goes.
Supersonic jets leave a lot to be desired as close combat support aircraft, and we do it much better than they do.