Solo,
In simple terms, depenting on the negotiated contract of the individual airline, A plan is the monthly retirement you're entitled to after leaving the company at 60. As I said it varies from one airline to the next. However, an example of it would be UPS wich pays you 1% for every year of service, based on your average ending pay (30 years= 30% of your average ending pay). Fedex and Alaska have a better A plan. The B plan is the lumpsum amount you recieve after retirement and, that works much like a 401k with some major differences. 1) The company solely makes the contribution. 2) there is a much higher government cap for it. 3) It's normaly deposited into a third party retirement brokerage account every quarter . Currently the best in the industry is around 11% to 12% of your yearly pay, for the airline of your choice, you can refer to the airline section of this site. I hope this briefly answers your question.