Virtually all domestic carriers are at two bags , 50 pounds each for check in with fees for overweight being applied pretty unyieldingly these days. Many overseas carriers were at 70 pounds and recently went to 50 (two checked bags).
Most luggage companies are now coming out with newer lightweight luggage , saving 5 or 6 pounds on 26 and 28" bags.
On our recent flights from Hawaii, American was also being very fussy about carryon sizes, numbers and weights.
Look on the website of your specific carriers .