Allegiant Air, which I fly frequently, just announced that they will be charging anywhere from $10 to $35 for each piece of carry-on luggage beginning in the near future. For those of you who don't know Allegiant, they are a budget airline, similar to Spirit, and offer absolutely no frills. Passengers pay extra to book their flights on-line, choose their seat, check baggage, get anything to drink, etc. They've been the least expensive option for me if I'm flying to Oakland, L.A., Las Vegas or Mesa, but they're going to be more expensive than the traditional carriers soon if they keep tacking on fees to everything.