I volunteer by flying dogs around the country to their forever homes. I can donate the cost of the flight (Fuel Maintenance etc) but only24% ofthecostisappliedtothereturn

I fly around the country for Pilots N Paws.  We donate our airplanes to fly dogs all over the country to their forever home.  
The organization, FAA, and IRS said that we are able to deduct the entire cost of the flight as well as the fuel cost, just not our time.  When I enter my costs into the deductions, only 24% is counted into my return.  Shouldn't all of my donation count?  Any help is much appreciated.  Thank you!