Things are in a rapid state of flux and could change on short notice, but, as of this writing, it looks like British Airways and Virgin Atlantic are each operating one nonstop flight daily from London Heathrow to LAX. There do not appear to be any flights operating from Gatwick to anywhere in North America. Traveling from Gatwick to Heathrow before flying is ...
It seems like flights are getting more expensive after COVID, see this new question here as to why:
Why are flights getting more expensive as traveling returns back to normal?
The best I managed to do is get the price down to £788 but that is with a lengthy stop-over:
(link to flight)