This was the first airline in Scotland, founded in 1933. In 1934 it was advertising Ulster as a 'Mecca of Tourists and Holidaymakers... a land of lilting mountains, bewitching lowlands and rugged coastal scenery'. Seemingly Ulster was chosen as a 'hub' for the company's services between Scotland and England. It used Aldergrove as its Belfast airport. The fares in 1933 from Belfast to Glasgow were £2 single, and £3 10s return.
The Scottish Screen Archive website has a clip from a silent movie from 1933 of a Midland & Scottish flight to Belfast from Renfrew. It'd be interesting to see the whole film. Click here