There are a ton of ways you can get to the airport, but we decided to return to Heathrow the same way we came - via the underground. Taking the Tube back to the airport is easy as long as you don't have 35 pieces of luggage. I had a carry on suitcase, and another large bag, plus a purse. I stood rather than sitting because I was afraid my bags would get in the way of people walking past. In retrospect, I recommend just sitting. Plenty of people did it and just tried to keep their bags as out of the way as possible. No one seemed to mind. I imagine everyone is used to it. The ride was quite long, so having a seat would have been great. On the other hand, I just kept telling myself it was my mini-workout for the day, trying to keep my balance and keep hold of my bags because the operator was a bit of a wild driver ;)
I think it's awesome when the public transport runs easily into the airport. It gives you another option instead of hiring a taxi. Of course with Uber, Lift, etc you do have some more options these days.
More From London:
Click to set custom HTML
You have a lot of options for getting around London from the Underground, Overground, TFL rail, to buses, taxis, uber, bicycle rentals, and even via the Thames river! Avoiding taxis will obviously save you a ton and if you plan to use the Underground during your stay, you can easily obtain an Oyster card at Heathrow airport.
After picking up a SIM card for our phone (cheaper than our international plan), we sauntered down a few steps down the hall to get our Oyster cards.
Be mindful that pricing for the Underground is relative to which zones you are traveling to and from. Knowing what zone your accommodation is in and where your destination is will be key. Sometimes by a short 5 minute walk to the next station you will have crossed into a new zone, making your trip cheaper than if you had hopped on at the closest station. Whether the effort is worth the savings is up to you, of course!
Check the cost of fares on many modes of travel on the Transport For London site here.