The game is still in beta stage and needs a lot of balancing. The game is probably to hard at the beginning (although the computer player plays quite predictable and should be easy to beat eventually)
The red plane is just as strong as the blue plane it’s just that when you hang over your own factory you get repaired automatically.
If you shooting at an enemy plane hanging over it’s own factory it’s very hard to kill beacuse it repairs itself. Although three to four sams/turrets, combined with you attacking the enemy plane yourself should be able to kill the enemy plane even though it is hanging over the factory.
I have found that some people find the game a bit hard to play. I will give you the following starting tips.
first build four soldiers programmed to occuppy a factory, and send them to the factory directly below the HQ. Then you should have just enough money to build one lighttank and one normal Tank programmed on hold and place them in front of the factory directly to the right of the HQ. These two units should be able to kill most enemy soldiers trying to occupy that factory. Now build more soldiers and occupy some more factories until you earn enough money to build some sams/turrets and you can start the counter attack.