Use of : Catch up

[UserEng]

I have to catch up flight vs i have a flight to catch up. Are both the sentences are correct and where can we use 'catch up with' ?

[Josef Essberger]

I think you mean:

I have to catch a flight.
I have a flight to catch.

Both are possible and correct.

Note that the expression is to "catch a flight", not to "catch up a flight".

We use "catch up" in a different way:

I have to catch up with my work.
I have to catch up with the leader.

[UserEng]

Thanks a lot...sir ..