The regular abdominal xray. Can you see an aortic aneurysm if I had one?

No. Usually not unless there was calcification in the artery walls that shows up on plain film. Otherwise ct scan.
Not best test. Usually not, since so many things like bowel gas block the view and vessels aren't seen well anyway. Ct or MRI can, though best screening tool is usually ultrasound. Screening recommendations exist, especially for smokers.
Most of the time if. If the aneuryism has sufficient calcification in it's wall, it would be visualized on a routine film of the abdomen, if there is concern that the patient might have an aneuryism, the better imaging test would be a abdominal ultrasound. If an aneuryism was found that was significant, usually over 5 cm in diameter, and ct angiogram would be done to determine the surgical approach.

Related Questions

The abdominal X-ray can see an aortic aneurysm if I had one, right?

No. A plain abdominal x ray usually can not identified aortic aneurysm unless calcified. You either have to have a abdominal sonogram or cat scan. Read more...
Nope. Only if it is calcified. The best test is an ultrasound. That can follow the aorta and is commonly used to monitor the aneurysm. A ct scan can see it as well, but is much more expensive. Read more...