Zoom, owned by the travel tycoons Hugh and John Boyle, and Flyglobespan, owned by industry veteran Tom Dalrymple, will sell seats on each other's transatlantic services.

The agreement came as Flyglobespan prepared to end a long-standing deal with Air Transat, the dominant airline between the UK and Canada, under which the Scottish company sold seats on Transat flights.

Hugh Boyle, Zoom's chairman, said: "It gives our flights more frequency. Under this arrangement, passengers have a wider choice of when they fly out and fly back, and the same applies to Flyglobespan."

But he said the two airlines' different approaches could present a barrier to a complete merger: "In Europe, Flyglobespan have a no-frills approach, whereas we have frills such as onboard entertainment. But as long as we can have a reciprocal agreement, this could continue."

Zoom and Flyglobespan, pioneers of cheap transatlantic travel, have been investing heavily in new capacity over the past year. Zoom, based in Canada, recently raised £5.7m to set up a UK operation for flights from Europe to the US.

And Flyglobespan has unveiled plans to fly daily between Glasgow and Toronto, along with other destinations in Canada, the US, Barbados and the UK.

The Toronto service is partly supported by the Scottish Executive's route development fund, which Scotland on Sunday last week revealed was under threat from a European Commission ruling.

Dalrymple said: "Canada was the foundation on which we built the Globespan name, and I have been very keen to get the airline flying Canadian routes."

The agreement between the Scottish travel bosses follows Air Transat's £20m acquisition of UK rival Canadian Affair.