Google "Air Law Online Test".
I've renewed my license twice now, with the air law component being the only written exam. My exam was FAA brand (Philippines) and I found a free online reviewer containing all the potential questions.
A couple of hours (boring) sitting the online tests and I was hitting between 90 and 100 percent.
Exam was a piece of cake.
Wouldn't advise this approach for all subjects but air law is soooo dull.
Hope you find something useful.
Best,
SSS