how would you say this about cost or fee
I will be paying the plane tickets fee.
I will be paying the plane tickets fees.
I will be paying the plane tickets cost.
I will be paying the plane ticket fees.

1. if there are more than one tickets waiting for payment. Should I say tickets?
2. I am not sure if it is fee or cost. If it is fee should I use the plural form?

Thank you!

Question

how would you say this about cost or fee
I will be paying the plane tickets fee.
I will be paying the plane tickets fees.
I will be paying the plane tickets cost.
I will be paying the plane ticket fees.

1. if there are more than one tickets waiting for payment. Should I say tickets?
2. I am not sure if it is fee or cost. If it is fee should I use the plural form?

Thank you!

Answer

Technically, you don't need either. The simplest way to say this would be:
I will be paying for the plane ticket(s). 
You can also say:
I will be paying the cost of the plane ticket(s). This, however, would not be heard so much in everyday speech. I would stick to the first example. Hope this helps. 
:)