which is correct?
More than one baggage is allowed
or
More than one baggages are allowed
which is correct?
More than one baggage is allowed
or
More than one baggages are allowed
If you look at the entry for baggage in the Cambridge Dictionary, you will see the letter U next to the word: that means it is uncountable, like sugar or leather.
You can't have one baggage, or more than one baggage, and you certainly can't have a plural baggages. You just have baggage.
The sentence can be fixed in one of two ways. You can replace baggage by bag, which is countable (note the C in brackets next to the dictionary definition):
More than one bag is allowed
Alternatively, you can talk about a piece of baggage, which is also countable:
More than one piece of baggage is allowed.