You can travel for free on all of the following services as long as you travel entirely within the Heathrow Airport Free Travel Zone.
••••Trains••••
• Heathrow Connect between T123 and T4
• Heathrow Connect between T123 and T5
• Heathrow Express between T123 and T4
• Heathrow Express between T123 and T5
••••London Underground••••
• You can travel free on the London Underground between T123 and T4 and T5 only if you have an Oyster Card or Contactless Card. You can also travel via Hatton Cross but you can not enter or exit at this station for free.
••••Non TFL Buses••••
• Abellio Surrey Route 441
• Abellio Surrey Route 446
• Abellio Surrey Route 555
• Arriva Shires Route 724
• First Berkshire Route 60
• First Berkshire Route 61
• First Berkshire Route 71
• First Berkshire Route 75
• First Berkshire Route 76
• First Berkshire Route 77
• First Berkshire Route 78
• Go Ahead Carousel Buses Route 730
• Go Ahead Carousel Buses Route 740
• Go Ahead Carousel Buses Route A40
••••TFL Buses••••
• Abellio London Route 350
• Abellio London Route 490
• Metroline Route 90
• Metroline Route 105
• Metroline Route 140
• Metroline Route 482
• Metroline Route A10
• Metroline Route U3
• RATP London United Route 81
• RATP London United Route 111
• RATP London United Route 222
• RATP London United Route 285
• RATP London United Route 423
• RATP London United Route H98
• RATP London United Route N9
• RATP Quality Line Route X26
••••Other Buses••••
• You can also travel free on all of the various different car park buses that run around Heathrow Airport. There are around 15 to 20 different routes.
••••Other Transport••••
• Heathrow Pods
••••You Can Not Travel For Free On••••
• National Express Hotel Hoppa Route H1
• National Express Hotel Hoppa Route H3
• National Express Hotel Hoppa Route H4
• National Express Hotel Hoppa Route H6
• National Express Hotel Hoppa Route H7
• National Express Hotel Hoppa Route H53
• National Express Hotel Hoppa Route H54
• National Express Hotel Hoppa Route H55
• National Express Hotel Hoppa Route H56
• National Express Hotel Hoppa Route H57
• National Express Hotel Hoppa Route H57X
• National Express Hotel Hoppa Route H58
• Any Coach Services
Hope this helps.
The following routes are not included in the Heathrow Free Flow Scheme
• Arriva Shires Route 724
• Go Ahead Carousel Buses Route 730
• Go Ahead Carousel Buses Route 740
• Go Ahead Carousel Buses Route A40
• Metroline Route A10
• Metroline Route 90
• RATP Quality Line Route X26
This is due to the routes either not directly serving the airport (90) or exits the airport directly onto the M4 spur toward Uxbridge (A10) and beyond (724,730, 740 and A40)
• First Berkshire Route 60
• First Berkshire Route 61
• First Berkshire Route 71
• First Berkshire Route 75
• First Berkshire Route 76
• First Berkshire Route 77
• First Berkshire Route 78
First Berkshire have as of IIrc 24 Sept changed the numbering of the above routes, the 75/78 have merged into the 7/N7 (24hr) serving T2,3 & T5 during the day and at night serving alternately Hatton Cross-T4-T5 or T2,3-T5 then both head to Slough, this service is free within the bounds of the airport, however it no longer serves Bath Road Compass Centre going directly to Colnbrook Bypass from T5