What are the chances of being bumped on a US airline even when holding a confirmed ticket?

NB: This is a guest article by Mike Putman, founder at TravelTeamConsulting.com.

Why do airlines oversell their flights? To "maximize" revenue, of course.

You see, back in the good ol' days of paper tickets and telephone reservations, you could make a reservation and have an "open" ticket.

Technically you can still do this, but it’s rarely done. During those times, the airlines didn't necessarily associate the purchase of the ticket with the reservation.

While this flexibility was good for the traveler, it wreaked havoc on load factors for airlines, especially on heavy business traveler routes.

Some flights could experience as high as 20-30% no shows. So a practice was accepted of "overselling" the flight.

Simply put, if a plane had 100 seats, the airline might take 120 reservations. Over time they became really good at predictive modelling and knew how many extra reservations they could take without having groups of people enraged at the gate.

Ever wondered why you can’t get a boarding pass in advance, and yet when you get on the flight 25% of the seats are open? Don’t blame your travel agent, and don’t buy the old airline adage,

You once might have heard:

"We need to keep those seats open for handicaps and pregnant women..."

Although there is some truth in the airlines adage, the bigger reason they hold back seats is so they can play the oversell game and not have to wait until ten minutes before departure to begin releasing no-show seat assignments.

Current day

A study on denied boarding for confirmed passengers can be found in the most recent published findings from RITA, Bureau of Transportation Statistics for the US (Q1-2011).

Airlines routinely oversell flights, no shocking news here. They do so in light of the vast majority of tickets now being non-refundable (sans Southwest).

As non-refundable tickets became the norm, however, you would think the "no-show" factor would drop accordingly.

Well it has and this is what has precipitated your odds of not being allowed to board a plane, even though you have a ticket (vis a vis contract) probably being higher than ever.

Most have heard a gate agent say "anyone willing to give up their seat on this flight, will be confirmed on the next flight and given a voucher worth $xxx valid on a future fligh", but what if no-one takes the deal?

Or what if the gate-agent or angry airline employee is having a bad day? The airlines have the right to not allow you to board. Alarmingly, there are airlines which have a much higher incident of this.

For example, you are almost ten times more likely to be denied boarding if you purchase a ticket on US Airways versus Delta.

Amazingly, Alaska Airlines and Air Tran reported zero denied boarding of confirmed passengers during the quarter in the stury, even when the pair had well over one million boards.

Therefore, your chances of being involuntarily bumped (aka denied boarding) even though you hold a confirmed ticket are: