The Timeline widget looks like this (iOS):
or this (Android):
We have four stages: Check-in, Boarding, Take-off, and Landing (you can swipe your finger on the stages to see them). For each stage, we show its closing time. For example, check-in at the airport counter ends at 7:15.
We then divide the remaining time - the time from the start of the stage to its end - and highlight it in color so that you can easily see your time constraints.
Color codes - Green/Yellow/Red