A whirligig is a pedal powered flying machine, built before the great war.
The Whirligig was conceived by Pinkie Pie, who built the original, pedal-powered Whirligig to keep up with Rainbow Dash and Gilda in the air. She later built an improved version and was seen using one in a memory orb. Whirligig's were fairly common before and during the war, improved versions using Spark batteries, much like pegasi operated carriages like the Sky Bandit. Littlepip and her friends discovered one of these atop the Old Olneigh Hospital and used it to escape the collapsing building.
Original Whirligig - Built by Pinkie Pie before the war
Improved Whirligig - Seen in a memory orb, used by Pinkie Pie
Griffinchaser II - A candy colored whirligig on the roof of the Old Olneigh hospital. Calamity repaired this Whirligig into working order.