I'm going to fly from Dayton, OH to Hochiminh City Vietnam in Jan 1, 2017. I'm planning to get 2 separate tickets, 1 from DAY to ORD, and 1 form ORD to SGN. There is 3.5 hours between these flights. I know that I have to re-checkin for the second flights. I have 4 luggage. Is it enough time to carry the luggage and check in? Thank you.