Journal Entries

This is for my friend, who just joined as accounts assistant in gulf ...

Around 50 employees working in his co. and every 2 year they will go for vacation, and at that time the co. has to pay their Air ticket fairs.

In this case, what will be the accounting procedure? Whether he has to make any provision for expenses every year? 

What is the way to assume the ticket fairs?

How it results in current year profit?

What are the Journal entries in current year and next year up to the payment of air ticket fair?

Thanks,