I flew from Shady Sanctuary to Valdrakken by purchasing a flight from the fly master in Shady Sanctuary.
The timer bar didn't show up even once when I was flying. ( I flew this route 3 times and relogged between the 1st and 2nd flight. )
I don't see the bar on other routes either.
It's up to retail.

When addon show bar, time is bad.

I have save +- 900 times across Azeroth fly paths from inFlying taxi timer addon.