Timeline widget looks like this (iOS): 

or this (Android):

We have 4 stages: Check-in, Boarding, Take-off, and Landing (you can swipe the stages to see them). For each stage, we show the closure time of the stage. For example, check-in at the airport counter is closing at 7:15.

Then we divide the remaining time - the time from the start of the phase to the end of the phase - and color code it so you can easily see your time constraints.

The Colored Codes Are - Green/Yellow/Red

Check-in (from the open of the online check-in, to the end of check-in at the airport): 50% - 45% - 5%
Boarding (from the start of boarding to end of the boarding): 25% - 35% - 40%
Take-off (40 min prior take-off, and the take-off time): 25% - 35% - 40%
Landing (take-off time to the landing time): 50% - 30% - 20%