What is the difference between to and for in the following statements?
I am headed to the airport.
I am headed for the airport.
The difference between heading to and heading for is subtle enough that you can use them interchangeably, yet I think there is a difference.
If you are heading to somewhere, you have a strong expectation of getting there promptly.
If you are heading for somewhere, you are going in that route, but there is some possibility of not reaching it, or making of stops along the way. An even less definite phrase is heading towards.
For example, imagine I was having a night on the town and a friend phoned to find out where I am. If I said:
... then my friend would probably infer that he should meet me in a pub at the top of town. If I instead said:
... then my friend is more likely to infer that he should meet me in some pub along that route.
There is an equally subtle difference between heading and headed. Once more, you can use them interchangeably, but heading is more active, and headed is more passive.
If you are the driver of a vehicle, or walking or running, you would be more likely to say heading.
If you are a passenger in a vehicle, or you're walking or running but you're following a leader rather than navigating yourself, you would be more likely to say headed.
Native speakers are unlikely to say either. What you might hear is I’m heading for the airport now.
Heading to somewhere is deliberate. It denotes an intended destination.
Heading for somewhere is not always deliberate, and denotes a direction rather than a destination.
You can also use "for" with the intended destination...
...however, you can't always tell whether that really is the destination if you do that.
Lots of people have given similar answers. Hopefully these examples illustrate the point in a way which clarifies any confusion.
There indeed seems a difference brought about by the preposition's meaning.
towards/ in the direction of -- not necessarily terminating at, [the airport]
destined -- not necessarily in the direct way, to [the airport]
I think there is some minor difference between the both.
But in most of the scenarios "I am headed to the airport" is the proper sign of good usage.