Best advice is to fill out this form:
https://live.nettracer.aero/southwest-paxview/lostandfound/landing.do?clk=GFOOTER-CUSTOMER-LOST-FOUN...
Depending when this happened you may also be able to contact the baggage office or airport lost and found - let us know some more details about your item, when and where it was lost, your flight info, etc.
Home airport MDW, frequent visitor to MCO to see the mouse.
