Would a routine, regular abdominal X-ray be able to detect an abdominal aortic aneurysm?

If calcified. If the wall of the aneurysm is calcified it may be possible to see it on a regular abdominal x-ray especially if a transtable view is obtained.
Get an ultrasound. Ultrasound is a superior test for detecting abdominal aortic aneurysms. It is non-invasive and does not require ionizing radiation (it uses sound waves). If you're a smoker, have copd, high blood pressure, or a have a family member with an aneurysm ask if you should be screened. Abdominal x-ray is not a good test for detecting aneurysms- it relies on detecting calcium and misses many!
Sometimes. If there is enough calcium in the wall of the aneurysm it may be able to be seen on plain x-ray. The best screening method for an aneurysm of the abdominal aorta is an ultrasound. This is non invasive and easy to do.
Sometimes. Calcified aaa's can be seen on plain films but most would be very poorly seen. Aaa's that are not causing symptoms are most often found when a physician is performing an imaging test, such as an ultrasound or ct scan, for another condition. Sometimes your physician may feel a large pulsing mass in your abdomen on a routine physical examination.