score:2
Unfortunately, hand/carry-on luggage must be compliant with the most restrictive rules of any carrier in the itinerary. This is different from checked baggage.
The reasons are entirely practical (I'm not aware of any 'rule'):
Air China has their carry on policy on their web site: Carry-on Baggage
"Each Economy Class passenger can take up to 1 piece of carry-on baggage."
Correct, they do not mention a 'personal item' specifically but there is anecdotal evidence out there suggesting truly personal items, such as handbag, are allowed. Note, this is not a guarantee and the gate staff can strictly enforce the rule at any time, sorry.
Upvote:5
Hand luggage (carry on luggage) is subject to each airline's rules. The "most significant carrier" rules apply to checked bags.
So you need to meet the most restrictive set of rules.