you always need the gas token to do whatever transaction there is but be careful though, make sure the airdrop you receive is truly legit, because there's possibility that some hacker trying to steal your money.

but if it's legit then you can just get some TON from exchange and send it to your wallet so that you can execute transaction, usually it's dirt cheap anyway since TON blockchain is known for its cheap fee and high TPS unless the project demand some TON of course.