CheapFlights.gr will find you the cheapest flights from Detroit to Philadelphia, comparing the cost of the flight to Philadelphia with 45 agencies, 5 booking systems and 718 airlines. Where to buy Detroit - Philadelphia plane tickets - it's up to you.
It should be noted that depending on the number of days left before departure, the price of a ticket for a Detroit - Philadelphia plane can change by more than 59%.
CheapFlights.gr suggests buying air tickets Detroit - Philadelphia in advance, then you can choose the conditions of the flight, focusing on your wishes and financial opportunities.