The aerial preparations for this weekend's Riverfire have begun, with Brisbane's CBD workers treated to an up-close view of a C-17A Globemaster on Thursday.

An aviation photographer, who has captured the previous flyovers, said it was the first time he had seen the military transport plane fly so low over the city.

The aircraft was due to drop to an altitude of just 100 metres on Thursday afternoon and cruise above the city skyline at 300km/h, according to the Air Force.

Photographer Tim Dwyer said Riverfire was one of his favourite times of the year.