Thank you! There's a pseudo-timer on the bottom right now that shows how far you are through the current flight (between passenger loading/unloading), but we're planning to add menus in a future update. Thanks for the feedback!
Now I know why I didn't saw the timer! I didnt saw it because I wasn't playing in fullscreen, and the game was like this:
Game in full screen:
(To switch a windowed game to fullscreen in windows, just click on the game view, then "Alt + Enter" and it will become fullscreen, some games won't be fullscreen)