What is maximum permitted mileage (MPM)?

How is a routing measured against the ceiling?

The measurement starts with the individual flight sectors in the itinerary. Each sector has a distance used for pricing, expressed in the distance unit that fare construction works in. Adding the sector distances together gives the ticketed point mileage of the whole routing, which is the figure that a mileage-based fare is tested against.

The test itself is a comparison, not a calculation of price: if the ticketed point mileage falls at or under the maximum permitted mileage carried by the fare, the fare fits the routing; if it falls above, the fare does not fit that routing as it stands. The ceiling is therefore a filter applied before the fare's other conditions are even considered, and it is one of the elements examined in fare construction.

Because the comparison uses the routing flown rather than the direct distance, two passengers travelling between the same two cities can reach different answers. A direct service may sit comfortably inside the ceiling while a connecting itinerary through a third point pushes the same journey past it.

Where does the ceiling come from?

The ceiling arrives with the fare. A published fare is filed together with a fare rule, and that rule carries both the maximum permitted mileage and the other conditions attached to the fare. The figure is not published separately as a general distance limit for a market; it belongs to the specific fare being quoted.

This is why the same city pair can show several different ceilings side by side. A cheaper, more restricted fare may carry a tighter ceiling, while a more flexible fare for the same cities may allow a longer routing. When fares are combined to build a journey, as with constructed fares, each component keeps its own ceiling for the portion it covers, and the rules for combining them decide how the pieces are put together.

What happens when a routing goes over the MPM?

Going over the ceiling is a pricing outcome, not a travel restriction. The itinerary itself is still flown; what fails is the fit between that itinerary and that particular fare. In practice the fare simply cannot be applied to the routing as it stands.

What replaces it depends entirely on the fare rule that was being used. The itinerary may be priced with a different fare whose ceiling accommodates the routing, the routing may be changed so that it comes back within the ceiling, or a provision written into the fare rule for longer routings may be applied where one exists. There is no single industry-wide answer, and no assumption that an extra charge automatically appears: where the rule provides a mechanism for routings beyond the ceiling, that mechanism governs, and where it provides none, the fare is unavailable for that routing.

For a traveller or an agent, the practical consequence is that an itinerary which looks cheaper on paper can become unavailable the moment a connection is added, and that the cheapest available fare for a longer routing is often a different fare rather than the first one quoted.

Which fares does the check apply to?

The check applies only to fares filed on a mileage basis. It is not a universal rule that governs every ticket: fares filed on a different basis are not tested against a mileage ceiling at all, so nothing about MPM can be assumed for a fare that does not use that structure.

It also does not apply to award charts. When a trip is booked with miles, the price comes from the programme's award pricing for the routes it covers, not from a ceiling attached to a published cash fare. A routing that would breach a fare's maximum permitted mileage can therefore be entirely bookable as an award, and the two questions should be kept separate.

Where the check does apply, it applies to the fare as filed, with its own conditions and its own date of validity. Nothing about one fare's ceiling carries over to another fare, another market or another carrier.

Limits and exceptions

• Staying inside the ceiling proves nothing on its own. A routing within the maximum permitted mileage only clears that one test; the fare's other conditions still have to be met before the fare can be used.
• Going over the ceiling is not a ban on the routing. Only the specific fare becomes unusable, and the journey can still be priced with another fare or as an award.
• There is no market-wide ceiling. Because the figure lives in the fare rule, a city pair has as many ceilings as it has mileage-based fares.
• Combined journeys carry combined ceilings. Where a journey is built from more than one fare, the construction rules decide how each fare's ceiling applies to its own portion.
• Scope is published mileage-based fares. Other fare structures and award pricing sit outside this concept, and rules described here should not be read across to them.

Related pages

Read next: ticketed point mileage (TPM), distance unit, fare rule, fare construction and constructed fare. Browse the full frequent flyer glossary.

Sources

Sources checked on 18 October 2026. No airline loyalty programme is described here: award charts, elite benefits and programme-specific award pricing are outside the scope of this page.

1. IATA Manuals, Standards & Regulations — Passenger Tariffs Conference Composite Manual (PTCCM), checked 18 October 2026