Ever wonder if that bag you checked, for a fee, is actually on your plane?  If you download the Delta Air Lines app, you can now track your bag on your mobile device.

Here’s Delta’s explanation for how it works: “Now when you download the latest update to the Delta app, you’ll be able to track your checked bag – just like you track a package,” said Delta on its blog. “Just enter the number on your bag tag receipt – or iPhone® users can scan the barcode – and watch your bag’s journey from departure to arrival and all points in between. Plus you’ll even know which carousel they arrive on!”

Delta says it’s the first airline to offer this service and the app is free. Of course none of this will provide much comfort if you are in New York City and your mobile phone says your bag is in Miami.

Delta, like most U.S. carriers, charges $25 per bag for domestic luggage.