Their forced hiatus was caused by the coronavirus pandemic.
Other historic and current military aircraft such as RAF Typhoons, Battle of Britain Memorial Flight Spitfires and RAF Falcons are also displaying at the event.
The new Red Arrows Team Leader, or Red 1, has choreographed fresh manoeuvres for the 2021 season while bringing back crowd favourites from previous years.
Watch: The Red Arrows break down the 'Boomerang' manoeuvre.
The show changes each year, with never-before-seen moves planned for 2021.
The season commences on 4 June and runs until 12 September.
As well as displays, the team performs flypasts to mark commemorative events and recognise landmark events within the UK and military communities.