Have you had to pick someone up from the airport only to end-up doing several laps of the airport because the flight was late? This sort of setback due to arrival delays is one of those modern day inconveniences that FlightCaster and their FlightCaster API hope to eliminate.
Travel reservation site Expedia starting working on its Expedia API back in 2009, according to the changelog. It has three APIs, covering hotels, flights and cars. Don't be shy. Expedia has been expecting you. The Expedia developer site has all the warmth and care of a fine bed and breakfast. They clearly want to invite you in, make you comfortable, and get your development project of the ground. Though they do have a couple hoops to jump through, as well.
Developers working on mashups may want to take note of a recent announcement by Ford that it intends to make SYNC, it's on-board vehicle system, accessible to developers next year. The general implication is that millions of vehicles could become platforms for all kinds of mashups and apps that integrate with various parts of the SYNC system, including its stereo and navigation modules.