Bombers
When the ships that follow you and drop bombs on the ground appear, other missiles will drop in frequency. Do not destroy them and use this time to cover some distance with less interference. When things become crowded, destroy the bombers and wait for them to appear again.
Weapons
You will be assigned a weapon randomly with each game. They can be changed by collecting the random gas bottles that are parachuted. The Flame Thrower is one of the better weapons, as is the shotgun. The laser is not recommended. Only change weapons if you end up with one that you do not like.