Get the UK fighters to Moscow to add extra defense. Buy mostly infantry and 1 tank a go. Launch attacks along the front at places where you are even in strength, but where there are no enemy fighters. Use your fighters to inflict losses in the attack
If it looks like you have killed 3 infantry, and he only killed 2, take that as a success and retreat. He will be down one more infantry than you and will have a harder time attacking your territory in the next go. USE RETREAT! Remember he has to reinforce from a greater distance. The more losses he takes at the front, the better, as long as your forces are a little ahead.