In the early 1920s there were over 60 operators in an area bound by Largs to the north, Kilmarnock to the east and Ayr by the south.

[1][2] Some regrouping took place in the late 1920s, and some members left to form Clyde Coast Services in spring 1929, operating between Saltcoats and Largs.

A mainly blue livery, with light cream round the window areas and a maroon belt was introduced for the owner's vehicles and over the course of 60 years the company would continue as a successful co-operative.

[4] A1 was slow to introduce 'one person operated' buses, only introducing them in 1983, primarily for evening and Sunday bus services,[3] despite unsuccessfully lobbying against their introduction by other operators to the area Traffic Commissioner,[5][6] and conductors continued on the arterial Ardrossan/Kilmarnock service well into the late 1990s, even under Stagecoach ownership.

The owners came to the agreement that they would approach Western Scottish, which had just recently become a subsidiary of the Stagecoach Group, and offer the company for sale.

[7][8] At the time of sale, Ayrshire Bus Owners (A1 Service) Ltd operated 97 vehicles,[dubious – discuss] owned by 10 members.

Some of the former A1 members continue to operate their own businesses, including Parkhouse Garage of Ardrossan (service station and car repairs) and McKinnon of Kilmarnock (haulage).

McMenemy of Ardrossan wound up their car repairs business in December 2004 and sold their premises to Clydeport plc, although the coach hire operation continued until March 2005.

Docherty Of Irvine had always run a parallel coach hire firm separate to A1 Service and ventured back into local bus operation around the Irvine and Kilmarnock area in competition with Stagecoach Western in the late 1990s, but sold its routes and associated vehicles to Stagecoach Western in October 2004.

The next day, Stagecoach rolled out 27 brand new buses in their corporate "swoops", spelling the end of the A1 livery after over 80 years.

Traffic Commissioners court battles took place between A1 Service and Western over the right to serve any new developments,[9] particularly the Chapelhill housing estate in the north of Ardrossan.