I know your joking, but some flights have been diverted to Paris where the airlines are bussing passengers to London! So yeah, there kinda is a replacement bus service for some flights!
> Perth Qantas customers who had their flights diverted from London to Paris after a massive power outage at Heathrow Airport will be put on buses to take them to take them to their final destination.
> https://thewest.com.au/travel/perth-to-london-flight-diverte...
> Perth Qantas customers who had their flights diverted from London to Paris after a massive power outage at Heathrow Airport will be put on buses to take them to take them to their final destination.