The Flyer 700/800/900 series were a series of transit buses built in three generations by Western Flyer and its successors Flyer Industries and New Flyer, of Canada, between 1967 and 1987. Except for brief overlap during transition from one generation to the next, they were not in production concurrently. All individual model designations included a prefix of either D, for diesel propulsion, or E, for electrically powered trolleybuses, with the first digit indicating the generation and the last digit indicating a variant within the generation. The introductory model was the D700, originally released in 1967 for the Canadian transit market, and the last series group to be produced, D900, was discontinued in 1987. Flyer had become New Flyer only the year before, in 1986.

The Orion I was a line of rigid high-floor transit buses made in 30-, 35-, and 40-foot lengths by Ontario Bus & Truck between 1976 and 1993 for the Canadian and United States mass transportation markets. The Orion I was the first bus offered by OBI and was available in transit (2-door) and coach/suburban (1-door) models. It was replaced by the rigid Orion V and low-floor Orion VI.