This provided the impetus for Air Inter to start scheduled services within metropolitan France, as well as between the mainland and Corsica.

[5] Air Inter primarily operated high-frequency scheduled internal flights from Paris Orly to cities in metropolitan France, principally Lyon, Marseille, Nice, Toulouse, Bordeaux, Strasbourg and Mulhouse.

Following the opening of Charles de Gaulle Airport near the northern Paris suburb of Roissy-en-France and the transfer of the bulk of Air France's international operations from Orly to Charles de Gaulle Airport from 1974, as well as the simultaneous transfer of UTA's Le Bourget-based operation to that airport, Air Inter began serving these routes from Charles de Gaulle as well (with the exception of Nice) to feed domestic passengers into those airlines' international networks.

Air Inter also linked Orly with additional second and third-tier provincial French towns as well as with all three commercial airports on Corsica (Ajaccio, Bastia, Calvi).

It was the only airline plying most of the domestic trunk routes within metropolitan France on a regular scheduled basis, especially from and to Paris.

Air Inter competed head-on with Swissair, the former Swiss flag carrier, between Paris Charles de Gaulle and Basel/Mulhouse.

In addition, UTA had limited rights to carry passengers, cargo and mail on the internal legs of its long-haul services, between Paris Charles de Gaulle and Lyon, Marseille, Nice as well as Bordeaux.

SNCF, one of Air Inter's two largest public sector shareholders, was also the company's main competitor on domestic trunk routes inside France.

This intensified when SNCF began high-speed, high-frequency Train à Grande Vitesse (TGV) services on purpose-built tracks from 1981.

[6][11] Air Inter was also one of the few European ultra short-haul, mainline scheduled operators to be profitable most of the time and was a forerunner of today's low-cost airlines in Europe.

From that day, any EU-based rival was free to compete on these routes, without restrictions on capacity, frequency or fares.

Dassault Aviation's inability to find other customers for the Mercure resulted in the French government granting Air Inter a subsidy of £10,775,000.