If you decide to try online dating sites be very discerning, especially with the "free" ones like Plenty of Fish (PoF). There are a significant amount of con artists using the sites. They download pictures of someone from the internet. Often signs of their fake identity is obvious, very poor use of English grammar (misspelled or missing words, incorrect use of plurals, pronouns, etc.). They tend to say things like how much you share in common, and how "stunning" you are. (I've seen that one a LOT). They'll prey on your sympathies (reassigned to a new city for work and being lonely, recently widowed, etc.).
The point is BE CAREFUL. If something doesn't "feel right", it likely isn't.
That said, I've met some very nice guys via online dating and am on PoF. No romantic keepers (yet), but have established some real friendships.
I think others have eluded to the fact that flying solo isn't all that bad either. My observation (in myself and others) is that it's important to find happiness as a single first. Don't look to dating to fill any voids. And remember there's a whole lotta love out there to be had and it comes in many flavors (friends, family, grandkids <one of my personal favorites>)!
Keep your head on straight, your heart open and best of luck!