I finally got around to thinking about this, and emailed a bunch of places (thank you google) for prices.
I was all set to go with LIALS-- their price was better than anyone else's. Then my husband suggested I check the BBB site, just to be sure.
OUCH. They had an F rating.
I think I'll go with the limo company my sister recommended. Yeah, we'll pay more. But we won't miss our flight.