I just recently returned from a very long haul trip (last month) and for us, social distancing was no issue during the journey home. No long queues at check-in, no long queues at immigration, and being in Business Class for the domestic leg then Premium Economy Plus for the long haul home, nobody within 3 feet of us. I agree, 3 feet is not the new so-called social distancing standard, but much better than having someone inches from us. On arrival LHR, again, hardly any queues anywhere. OK it was just as the UK was starting to lockdown but there were people inbound. We just found that waiting a little made what queues there were more manageable.
Our plan pre-COVID-19 was to have another long haul holiday in 2022 and I suspect I'll be either looking at Business or First Class or even going by private charter. Expensive ? Of course it is, but our health and well being is far more important and if it comes to it, we won't travel abroad again. Drastic I know but it comes down to choice. The airlines won't have a choice because they need bums on seats but as consumers, we do have a choice.
It's life Jim - but not as we know it !