To get the best response and performance from AI you have to take a measured approach to the way you issue commands. Just hitting the attack key at the sign of the first target is not enough. You have to understand how the AI attack responses are coded. When flying with a flight of 4 or more, the flight is divided into multiple 'two-plane' elements -- you and your wingman are element one and you are 1 and 2, the next element is 3 and 4 and so on. So in a flight of eight planes you have four elements to work with.
When attacking ground targets or sea vessels, you have to padlock a target first. If you hit the attack key (A) once, only your immediate wingman will respond and attack that target. If you hit the attack key again for that same target, the next element (3 and 4) will go in after it. Another attack command and the third element of 5 and 6 will respond.
Now, in order to manage a surface attack properly and spread the love around, padlock one target, hit the A key and let your immediate wingman respond, then padlock the next target, hit A again to get the second element 3 & 4 to go after that one. Padlock another target and 5 & 6 will go after that one. Make sure you're still a mile or two from the target area as you select the individual targets and issue commands. Don't go in first until you have done this. Then you can race in, hit and run and watch as your wingies go after their assignments.
Attacking ground and sea targets with AI is different than in dogfights. In a furball, if you hit the A key twice rapidly, the wingies will go after the closest bogey they can find (unless they're rooks, then they may wander a bit before engaging). If you hit the A key twice in attacking ground or sea targets, the AI get confused about which ones will go in first and to which target, so consequently they seem to lose interest in your mission. So you have to be careful to think in terms of which elements will attack which individual surface targets and command them by element, not as a gang.