It depends on which way you are converting whether you call it a lower or higher rate.

Since we are discussing people arriving in JA, people are exchanging their currency for $JA and GET a lower rate.
At cambios/banks, currently they give you about $84JA for each $1US you give them.
The airport cambio will be less - I don't know exactly now, but they will give you something like only $80JA for each $1US you give them.

But when leaving JA, people are turning in $JA for their home currency. You are right that then they have to PAY a higher rate.
At cambios/banks, you will have to give them about $87JA for them to give you $1US.
At the airport, you will have to give them something like $90JA or more for them to give you $1US.

How about we just call it a worse rate at the airport - accurate either way.