Flight is taken in 308 TLDs and developed in 17. There are 94,305 domains including the singular. There are 16,480 companies with the term "flight" in their name.
Flights is taken in 175 TLDs and developed in 9. There are 25,960 domains including the plural. There are 1,295 companies with the term "flight" in their name.
Of course perhaps one thinks it's the pairing with now that makes the plural more powerful
FlightNow is taken in 9 TLDs with the .org, .net, .online, and .shop live (4 companies).
FlightsNow is taken in 7 TLDs with the .net and co.uk live (2 companies).
I always say it's best to follow the data. We can think something sounds better to our ear, etc - but data shows us what companies actually choose. And that's much more important than our personal perspective.