I've been making lots of fajitas lately so I've had to get to know about the different types of meats you can use. I once thought flank, hanger and skirt steak were the same meats with different names. I was wrong - and you won't hear me say that too many times! Just kidding. But yes they are three different meats. What is similar is that they all can be a bit tough and all need to be sliced against the grain.
The skirt steak is thought to be more tender with a great beefy flavor. It's a bit fattier (which is probably why I like it) which means more juicy and is a great steak for fajitas. All of these meats benefit from a either a rub or a marinade to help break down the tougher fibers. These meats also need a high temperature grill. Cook it fast and keep it on the rare side or it will be dry and chewy. The grain is pretty easy to see and make sure to carve it perpendicular to the grain.
Most of us are familiar with flank steak as it's also sold as London Broil. It can be used for fajitas and in fact the pictures in my fajita recipe show the flank steak - although I do prefer the skirt steak. Flank is a very lean steak although it can be tough - so make sure that you carve thin slices against the grain. I don't think it has the same great flavor you'll get with the skirt steak though.
The hanger steak has been used for quite some time in French Bistros. In fact if you google Bistro Steak you will run into hangar steak! It's also used in bistros as Steak Frites. This steak can be used for fajitas just cook it on high heat and keep it on the rare side. It's making a resurgence in the states now and you'll see it on many menus. Due to it's rise in popularity and that there is only one on each cow the price is going up on this once cheaper cut. Although it's still less than other steaks.
To sum it up - for my money - I will choose skirt steak first although I have and will continue to use the others as well. I like skirt for it's fattier, juicier and more flavorful qualities. That said all of these can be used without a huge difference in taste. And if you rub them first with Baja Border Blend, cook them on high heat, keep them fairly close to rare and slice them against the grain the difference will not be perceptible to most palates!
For another take on this - check out this link for a tutorial on these meats with a fun diagram of where you will find these different meats on a cow.