that's a nice goodwill store find you got there.
People sell skyway luggage keys on ebay, but you have to get the correct key code. here's an example of such a key:
http://www.ebay.com/itm/161790830207 but no guarantee that it would work on your suitcase.
Here's another one for less $$
http://www.ebay.com/itm/321833911006Same one for $4.50 with free shipping
www.ebay.com/itm/291517784324and it's starting to look like they all have the same key code.. be worth to spend $4 bucks to find out =)
So, we normally pick locks for a hobby here, but not usually vintage suitcase locks, so I'm out of any other ideas for any quick tips or tricks on that sort of lock, maybe stop by a local locksmith shop and ask if they can stick something in the keyway that they have in stock which may be the correct key code and pop that open for you.
good luck
Squelchtone