Same is happening to me today. Checking on dl speed in Task Manager shows 184kbps, so MSFS 2024 is not downloading/streaming anything and taking forever to load. Funny enough just did a speed test and my internet is stable at over 500mbps.
I wonder if they’ll ever acknowledge this as an issue and provide a fix.
Had the same issue and solved it by turning off live traffic and multiplayer.
Same here, trying to get into a flight from career mode and it just hangs?
What got me in was turning the TLoD down to 10. Then turn it back up once you’re in. Started a flight nearly every time for me.
See related reports:
Long loading/infinite time for free flight after pressing "Start flight" - LOD reduce as workaround
Can't start a flight, just get a loading circle when clicking 'start flight'
Thank you so much, I was pulling my hair out trying to fix this.
Your workaround worked great.
Glad you found that workaround! Thanks for sharing!
Hope they’ll fix it soon.
Same here, workaround is not working for me 
AsoboReport-RunningSession.txt (28.0 KB)
btw - is there any update on this? The workaround with temporary reduction of TLOD does not work for me…
…this game is really starting driving me nuts…it is out since months and those day-1 bugs are still there…long loading screens, this utterly laggy controls selection menu and actually each aircraft coming with the prem deluxe edition being full of bugs…just to call out a few…very disappointing experience imo
I was able to solve it. It was due to one small scenery folder in my community folder.
I had removed everything from my community folder and started adding everything back 5 folders at a time. Each time after adding I started the sim to see if I could load a second flight.
At one point it stopped working, so I added each folder separately of the five causing the bug, until I found which one was giving issues.
The only thing I could think of about this scenery piece, is that it slightly overlapped with another scenery object.