The flight from Heathrow never looked like it would leave on time. Here's a close-up of the departure board (I was on VS039):
That comes from this bigger picture:
Yes, the gate was openin in exactly one minute ago's time. It eventually opened at 10:46, so we could enjoy the 10-minute walk to the gate ready for the 11:15 take-off.
At 12:30, we actually took off.
Amazingly, though, we actually arrived at Chicago on time, at around 15:20. So, you lose some, you win some.
Then you lose some again. My flight out is scheduled for 17:08. It took 45 minutes to clear Passport control. Nowadays, they want to scan four fingers of right hand, four of left, both thumbs then look at the camera. All the while, they're asking you what you're going to do in the USA. Meanwhile, US citizens breezed through; they had to wait 45 minutes for their luggage, mind you (I encountered the man I had been sitting next to for the whole flight as we waited for the inter-terminal shuttle).
By the time I got to terminal 1, things were looking decidedly late. I had to go through security again (shoes off, laptop out, unlike at Heathrow), but ... just a moment. It turns out my flight has been delayed and will be leaving at 18:00 rather than 17:08.
So that's how come I get to type this rather than stand in a ticket line trying to book a later flight: my scheduled flight is already a later flight.