There's a way to gain money faster, you can start mass production of a weapon, for example laser pistol/rifles and sell them.
They are fast to produce and you don't need too many engineers/space
Also, you could do special mix to optimize the production, but you need to study a bit for that
Flying suits are great, 6 men well equipped can easily clean a huge alien-battleship, the worst part are mind attacks, it's hard to train your unit at the beginning, but tanks are immune to those kind of attacks.
And remember you can save your progress, loading a savegame could save your base from huge attacks, they are random.