“Flying”, from the 1967 release Magical Mystery Tour, was the first song credited as being written by all four members of The Beatles. The writing credit is attributed to “Lennon/McCartney/Harrison/Starr”. It’s a simple 12-bar blues chord progression instrumental track, though it does include some chanting.
It was rare for The Beatles to record instrumentals, and it was also rare for a song to be credited to all four members of the band.
“Flying” was originally titled “Aerial Tour Instrumental”.