Airlock? We don't need no stinking airlock!
I have fermented the last 4-5 batches with either foil over the carboy neck, or a solid lid on my plastic bucket (it is the right size, but lid & bucket are not same brand, so it doesn't lock down. Basically controlled open fermentation. I only keep beer in for about 2 weeks, and it has been working well.
For my mead that is bulk aging under an airlock, I use vodka.