The plane bringing home Corporal William Savage, Fusilier Samuel Flint and Private Robert Hetherington has just landed at RAF Brize Norton.
Close family will spend time with the coffins before the cortege passes through the village of Carterton where friends and family will pay their respects as a memorial bell tolls.
More top news
The band announced at a free concert on Friday that they would take over the event's Pyramid stage on Saturday June 25.
The victims were collecting permits and escorts a day after their home town was liberated from the extremists.
Scotland Yard said the male youths will appear in custody at Westminster Magistrates' Court on Saturday.