HA and AA are in different terminals (AA in T4, HA in T2). To the best of my knowledge American doesn't have a shuttle bus running airside between the two terminals, which means you'll have to exit and we clear security. Additionally to get between the two terminals the quickest way would still probably take you about 15 to 20 minutes. The airport is quite crowded at that time of day, so walking is probably your best bet, yet it's not close. If you wanted to take a shuttle bus you could do that, but the shuttle bus only goes in one direction so you would have to go the long way around. I wouldn't risk it in only 1 hour and 15 minutes.