difference

[cro]

I'm afraid we have had to cancel the flight because of bad weather conditions.

and

I'm afraid we have to cancel the flight because of bad weather conditions.

Let me get this straight, I really am confused about using have, had, have had, and had had.

Help me pls....

[svartnik]

I'm afraid we have had to cancel the flight because of bad weather conditions.

and

I'm afraid we have to cancel the flight because of bad weather conditions.

Let me get this straight, I really am confused about using have, had, have had, and had had.

Help me pls....

have to -- simple present -- one syntactical unit (semi-modal verb)
have had to -- present perfect -- this is one syntactical unit: the verb "have to" in present perfect tense

Have to -- simple past: had to -- present perfect: have had to -- past perfect: had had to