The most common and most likely answer to this crossword clue is the 3 plus 3 letter word JET LAG
J
E
T
L
A
G
More clues leading to the result JET LAG
- Black girl returned in a state of exhaustion
- Issue when travelling in Spooner's rented car
- Problem for long-haul traveller let loose in expensive car
- Travel sickness in Spooner’s rental car
- Flight delay causes travel sickness
- Occasionally rental in posh car may be a problem for traveller
- Let off in posh car, getting traveller’s complaint
- Physical consequence, being let out in fast car?
- Traveller’s ill feeling let out in car
- Shoot convict, getting whacked after flight?
Buddy explains!

The straight part
We know that "a problem for traveller" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a problem for traveller = jet lag.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.