This guide is specific to obtaining free round trip Northwest tickets while travelling to and from Ithaca. But in principle it can be adapted to any other itinerary.
(i) Buy a Northwest ticket to return to Ithaca at the end of Thanksgiving/ Cornell Winter Break/ Cornell Spring Break. (Yes you have to pay first - nothing is absolutely free!)
(ii) While waiting in Detroit to return to Ithaca, stay near the gate and look out for oversold announcements. The flight is likely oversold on these dates.
(iii) When they ask for volunteers to take the next flight, IMMEDIATELY jump to the podium and
be the first to volunteer.
(iv) Enjoy your free hotel room, meal vochers, and FREE round-trip ticket.
(v) In principle, you can keep on volunteering - ie. volunteer when it oversold again on the next flight, and the next, etc...
I am the proud owner of 2 free round-trip tickets. Too bad I had to come back. They had once again asked for volunteers on my flight back, which would have meant a 3rd free ticket...