No, you can't deduct what you paid. To deduct a charitable contribution you have to pay it to the church or other charitable organization and get a receipt from the organization. You can also deduct your own out-of-pocket expenses when you perform services as a volunteer for the organization. But you can't deduct a church employee's expenses that you paid directly.
In the future, donate the money to the church, and let the church pay the pastor's travel expenses.
