There is not much difference accept the name.
So really they are the exact same thing.
The UK spelling is "summer fayre" (a local or regional festival).(The actual Middle English spelling was faire so the spelling is pseudo-archaic.)
fayre
Brewers Fayre was created in 1980.
The duration of Glastonbury Fayre is 1.45 hours.
Glastonbury Fayre was created in 1972-05.
Barbarous English Fayre was created in 1989.
Glastonbury Fayre - album - was created in 1972-04.
The US spelling is fair (festival, pageant) but some venues, mostly in the UK, use the pseudo-archaic form "summer fayre."
Eleanor Fayre died in August 1997, in Sussex, England, UK.
Eleanor Fayre was born on August 16, 1910, in South Wales, UK.
Eleanor Fayre's birth name is Eleanor Mary Tydfil Smith-Thomas.
The cast of Glastonbury Fayre - 1972 includes: Linda Lewis as Lind Lewis Steve Winwood as Traffic