Maximum Permitted Mileage (MPM)

Maximum Permitted Mileage (MPM) refers to the maximum number of miles that may be flown when using a published international fare between a specific origin and destination.

It is a fare construction rule that ensures a passenger’s routing remains reasonably direct relative to the geographical distance between the two points. 

MPM values are established based on the shortest combination of nonstop sectors between cities, sometimes including designated construction points, and then typically increased by a tolerance, commonly about 20 percent, to allow practical routing flexibility. 

By setting a maximum allowable distance, airlines can permit reasonable connections while preventing abuse of fare rules.