PSA No Heathrow Express nor Elizabeth Line November 15, 16

Thanks for the heads up. Of course, this is on our day of arrival!
What are other options from Heathrow to London? (other than a very expensive taxi)

Hi Diana, I’m going to defer answering about other methods of transportation in to some of the folks on here who are so knowledgeable. I would assume that taxis are going to be very expensive as you said, and probably harder to come by on those days. The bus system was my first thought. Hopefully, some of our travel “agents” will chime in today to help with this.

The work is in the tunnels at Heathrow. So the Elizabeth Line is starting from Hayes and Harlington to Paddington.
So you can take a local bus or taxi to Hayes and Harlington station then the train.
The buses are #SL9 and 278 from Central Bus Station (Terminals 2 and 3) or #350 from Terminal 5.
I would be inclined to try to beat the crowds and board the train at West Drayton (the next station west, also in Zone 6). Bus U3 from CBS or 350 from Terminal 5.
However due to other engineering work the Elizabeth Line is closed in central London east of Paddington with trains terminating in main line platforms at Paddington, not in the Elizabeth Line sub surface platforms.
So the Piccadilly line tube may be the best way, depending where your hotel is.
Or change to tube at Paddington.

The Underground is an obvious option, especially depending where you are staying, in fact, in a half dozen trips to London, the only option I have taken. The Piccadilly line takes you right into the heart of London with some easy cross platform changes along the way to several other lines.

for Diana from the World -

where in London is your hotel? That allows more precise answers... it may be one route, it may be another

Thanks all!

Nigel: We are staying very near Tower Hill Station. Thanks for your help!

If you're staying at Tower Hill, the best choice is to take the Piccadilly Line to Baron's Court or Hammersmith (at those stations, you can make the change in the same direction by just walking to the other side of the platform with no lifts or stairs) and then take a District Line train to Tower Hill.

In truth, for getting from Heathrow to Tower Hill the Piccadilly/District or Circle line route would be the most sensible;e even is the HEX and Elizabeth Line were running normally.

The Piccadilly trains from Heathrow will no doubt be a bit busier on that weekend but you still have no trouble getting seats and room for luggage as the trains start there.