No, the Heathrow Express is not covered by a standard London Travelcard in 2026. While you can use a Travelcard for almost all Tube, DLR, and London Overground services, the Heathrow Express is a premium, privately operated rail link that sits outside the Transport for London (TfL) fare-capping and Travelcard zones. If you have a Travelcard that includes Zone 6, you still cannot use it to board this train without paying a significant supplement or buying a separate ticket. However, for a more budget-friendly option in 2026, the Elizabeth Line is covered by Travelcards (and contactless capping) and serves the same stations at Heathrow for a fraction of the price. The only way to "use" a Travelcard for the Express is if it is a "National Rail" paper Travelcard with a specific "Add-on," but for 99% of tourists using Oyster or digital Travelcards, the Heathrow Express requires a dedicated, premium-priced purchase.
Heathrow Terminals 2 & 3 is a London Underground station at Heathrow Airport on the Heathrow branch of the Piccadilly line, which serves Heathrow Terminal 2 and Terminal 3. It was named Heathrow Terminals 1, 2, 3 until January 2016, when Heathrow Terminal 1 was closed.