Why Flight Tracker?

Most likely, I want to use a flight tracker in one of these three situations:

1) Somebody dear/important is coming to my town/country and I want to know when is the flight landing and when has it taken off (on time, later)?

2) Somebody dear/important has gone to some other town/country and I want to know if he/she has taken off, or has arrived OK, or why he/she is not calling/SMSing.

3) When I am getting ready to pick up someone at the airport and I want to know the status of the flight (i.e. whether it is on time, delayed, or canceled)

4) When I am getting ready to take a plane and I want to know the status of the flight (i.e. is it on time, delayed, or canceled)

5) When I have a connecting flight and I want to know if it is on time or has been delayed.

What Information Do I Want from a Flight Tracker?

Averaging among all these circumstances, I want to know whether the flight…

1) … is scheduled to take off on time – departure time?

2) … is scheduled to take off later – then when?

3) … has taken off – when?

4) … has arrived – when?

5) … is estimated to arrive on time – arrival time?

6) … is estimated to arrive later – when?

And of course, I want to know if everything is OK with the flight (i.e. it is flying en route, is not hijacked, has everything functioning properly, etc).

Also, I may want to know the weather in the departing and arriving locations, the type of aircraft, the percent of departures / arrivals on time…

Do you have to add anything? Please do, as a comment.