What kind of class/good paying job should I take/go for?

Four months ago, I decided to go back to school because I wasn't having any luck finding a job after being laid off. I took a C.N.A/Med. Aide course and my husband paid for everything. Immediately after completing the class and passing the text, I found a job which was fortunate because my husband got laid off. It's time for me to return the favor so I'm looking into some classes he could take that are under 6 months long so he can get a license or diploma or certificate that will allow him to find an in demand job that pays well. What kind of class should he take?