Fighters are OP. They shouldn’t be better in almost every way over bombers.
They cost less, have more hp, use up one slot, deal more damage to buildings then they should, faster speed, slow down buildings and have an area attack on troops.
Remove the slow from the fighters and give it to the bombers and reduce the damage the fighters deal to buildings.
To be fair Gavin, are you talking about fighters in general or maxed fighters?
If you're talking about fighters in general I say they're not OP especially in IA or early Global as air defenses take them out easily if you don't use them well.
Once they're upgraded several times they become powerful and rightly so. It takes a lot of time and resources, as many have pointed out, and we want to see rewards for our efforts.
Also, as people become more experienced they use better strategies with their planes. This is another reason they might seem OP, people are using them well and bringing them home, so they might seem invincible. Trust me they're not.
Many a time I've had to massage my planes or not use them at the end of a battle because they were so badly damaged.