This is already in the 2Do list.

Burst lenght is in development. You'll have to decide in advance if you want to use Burst during the Fire phase. You can give a limit depending on the Combat Value, so you will be able to say "use Burst lenght if combat value is more than <your value goes here>".

Lewis gun won't be there in the first release, but there will be space for them in future enhancements.

Mhmm, this could be a big problem for German planes.
Let's think to this scenario: I fly an English plane, and I choose to spent some fuel flying toward north. You fly a German, and if you want to hit me, you need to follow me .
After you depleted your fuel, I turn my plane and you are an easy kill.