Even great helicopter pilots will tell you the attack chopper is a flying coffin. You can be the best pilot in the world and still be easily shot down simply because a lot of maps have no cover for the chopper and there's 40 bazillion things that can take it down.
The scout on the other hand is a beast for no other reason than you can have engineers repair it on the fly and it's quick, so you have a flying fortress of death that can tank hits and deal lots of damage. You can have multiple people firing at it with stingers and it will limp away and come back full force. It's a bit silly. It has all of the advantages and no weaknesses essentially.
Close!
Not going to count things that require actual aim, this is just a list of things that lock on to aircraft (probably forgetting some):
Attack Jet: Heatseekers
Stealth Jet: Passive & active radar
Attack Helicopter: Heatseekers
Scout Helicopter: Heatseekers
Mobile Anti-Air: Heatseekers, passive & active radar
Main Battle Tank: Gunner SOFLAM
Infantry Fighting Vehicle: Gunner SOFLAM
Attack Boat: Passive radar, laser-guided in tandem with a gadget lock
Infantry: PLD, SOFLAM, Stinger, IGLA, Javelin in tandem with a gadget lock, anti-air mines and HVM-II as a pickup
Of course none of that shit actually hits the jets, so the choppers take the brunt of it. And as zma noted, the Scout chopper
can survive (unless Elzar's piloting) provided you have someone repairing, but even then, being in the air becomes more a game of hide and seek than actually providing support for your team. The MAA alone covers like 70% of a map just sitting outside its base. It's out of control!