Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from St. John's to Columbus as you normally would.
St John's (YYT) is the airport you will fly out of if you book a flight from St. John's to Columbus. You should not have trouble finding flights to Columbus from St John's; the airport handles an average of 0 outbound flights to Columbus per day. You should also have plenty of airline options to choose from since 0 airlines have flights from the St. John's airport to Columbus. It is only a 6.7 km journey to St John's (YYT) from St. John's’s city centre.