From what do you judge airdrop is a lie?. Not all airdrops are lies or scams. In the previous time, I also joined a lot of airdrops, and most of them were scams like you said. But, not a few also give me profit with little tokens.
Before you joined Airdrop, the first thing you must look is how the project products, teams from the community, and others. If your judgment is good in this case, i don't think you will waste your time. My advice, follow up airdrop line with ICO and observed a response of investors to the project.