### Clue: Flyer complained after vacation about flying Ryanair across Belgium (6-4)
### Answer: CANARY-BIRD 
 ### Explanation: Definition: Flyer
A double envelope ('about' and 'across') of B ('Belgium', IVR) in ANARYIR, an anagram ('flying') of 'Ryanair' in CD ('**C**omplaine**D** after vacation'),