It would depend on whether you bought the ticket for leisure or for business. If for business, you would have deducted the ticket's cost from your income. In that case, if you received compensation or a refund, you would have to add that back into your income to be taxed. But if the trip was for leisure and the ticket's cost was not deductible, any compensation you receive would just be like a reduction in the price you paid for the ticket. Not taxable.
I'm not a tax accountant, but that's how I would look at it.