Wi-Fi available on all American Airlines aircraft and selected British Airways planes, see below list of British Airways’ Wi-Fi-enabled aircraft:

Aircraft type: 747 -400
Registration 
G-BYGA
G-BYGC
G-BYGD
G-BYGE
G-BYGG
G-CIVR
G-CIVS
G-CIVV
G-CIVW
G-CIVX
G-CIVY
G-CIVZ
 
Aircraft type: 777-200
Registration 
G-RAES
G-VIIC
G-VIID
G-VIIE
G-VIIF
G-VIIG
G-VIIH
G-VIIJ
G-VIIL
G-VIIS
G-VIIY
G-YMMD
G-YMME
G-YMMF
G-YMMJ
G-YMMK
G-YMML
G-YMMN
G-YMMO
G-YMMP
 
Aircraft type: 777-300 
Registration 
G-STBA
G-STBB
G-STBD
G-STBE
G-STBG
G-STBL
 
Aircraft type: A380
Registration 
G-XLEG