If staying near Hammersmith or Earl’s Court, the Piccadilly line offers a straightforward

https://www.scribd.com/document/1074929924/National-Rail-to-Heathrow-Routes-Transfers-and-Tickets-Explained-232993

If staying near Hammersmith or Earl’s Court, the Piccadilly line offers a straightforward, single-seat ride to Heathrow without needing to change trains.