In the Bag by Kate Klise (2012)

As light and fluffy and delicious as cotton candy, this is a novel told from four perspectives: A mother and daughter traveling to Paris, and a father and son traveling to Madrid to work on an art installation. A glass of spilled wine, and two similar looking bags lead to a note left in a carry-on, mixed up bags, surreptitious email conversations, faking sickness, and planned meetings in Paris and Barcelona.

Dishy and light and fun, with realistic, charming characters.  Klise will definitely be an author I'll keep an eye out for again.