The boarding procedures of airlines often differ from airline to airline, and it's a good idea to be familiar with the various kinds that exist. That way, you will know what to expect when it's time to board your flight.
Reverse Pyramid Boarding
Reverse pyramid is one kind of boarding procedure, and although it is not widely used, it is an effective way for boarding passengers. Until recently, US Airways used the reverse pyramid boarding method. This means that top frequent flyers and Star Alliance Gold elites from partner airlines are seated first in First Class or Area 1 and Area 2. Non-elites are then seated in areas 3 to 5. After seating passengers requiring extra assistance, US would board those passengers who had seats in the rear of the plane, starting with the furthest back, and so on, until everyone is boarded.
Rotating Zone Boarding
Another popular method of loading passengers is rotating zone boarding, which is used by AirTran. In this case, Business Class passengers are first to board, followed by the seats in the back five rows of the plane. Next comes the first five rows of coach. Hence the name, as boarding rotates back and forth between the back and front zones of the airplane.
Outside-In Boarding
United Airlines prefers the outside-in boarding plan, which is also referred to as "WiMA," (Window, Middle, and Aisle). This process is intended to speed up boarding and eliminate the scenario of a person seated in an aisle seat, who has to get up to let the passenger in the window seat by.
Rear-to-Front Boarding
The rear to front method of boarding is popular on American Airlines flights, as well as many domestic and international carriers. After first class passengers and those with special needs are boarded, passengers in the rear zones are loaded, followed by the middle zones and then the first zones of coach.
Zone/Block Boarding
Delta Airline employs a zone/block style of boarding that divides the airplane into as many as nine zones. First class passengers and those in the front rows of Coach are in Zone 1. Zone 2 passengers, consisting of Delta/Northwest's Elite Frequent Fliers, board next. Delta's partner airlines' Elite members then board in Zone 4. The other zones are loaded from the rear to the front of Coach.
Random Boarding
Southwest Airlines uses random boarding. That means Southwest doesn't assign seats, so getting into the first seating group is highly desirable. Otherwise you may end up in a middle seat. There is some sort of boarding order in that the time you check in determines what boarding group you will be part of. The earlier you check in, the more chances you have of being in the earlier boarding group. Passengers are able to chose their own seats regardless if it is in the front or rear of the plane, or in the window or aisle.