The aim is to create a red-and-white wall of support to back United in the pursuit of a second trophy this season.
The hats and flags follow on from the success of the red-and-white scarves that were placed on every seat of the thousands of fans who cheered the team to victory in February's Carabao Cup final.
The flags, made from recycled plastic bottles, will bring a vibrancy to the United end as we aim for a 13th FA Cup success in the club’s 21st appearance in the final. After the game, any flags not taken as souvenirs will be recycled.