Frank Whetstone International Airport or Del Bonita/Whetstone International Airport (FAA LID: H28, TC LID: CEQ4) is a public use airport at the Canada–US border, in Port of Del Bonita, Glacier County, Montana, 2 nautical miles (4 km; 2 mi) south of Del Bonita, Cardston County, Alberta. The airport is owned by the U.S. state of Montana and is operated by the Montana Department of Transportation Aeronautics Division. It is located 31 miles (50 km) northwest of the city of Cut Bank, Montana.

The airport has a runway located on the border, with aircraft tie down areas in Canada and in the United States. It is classified as an airport of entry by Nav Canada and is staffed by the Canada Border Services Agency (CBSA). CBSA officers at this airport can handle general aviation aircraft only, with no more than 15 passengers.

The airport is one of six airports that straddle the Canada–US border. The others are Avey Field State Airport, Coutts/Ross International Airport, International Peace Garden Airport, Piney Pinecreek Border Airport, and Coronach/Scobey Border Station Airport.

The airport covers an area of 14 acres (6 ha) at an elevation of 4,336 ft (1,322 m) above mean sea level. It has one runway designated 7/25 with a turf surface which is 4,440 ft (1,353 m) or 4,401 ft (1,341 m) long and 65 ft (20 m) wide.

For the 12-month period ending April 27, 2016, the airport had 110 aircraft operations: 73% general aviation and 27% military.

• List of airports in Montana
• List of airports in Alberta

• Aerial image as of August 1995 from USGS The National Map
• Resources for this airport:
  • FAA airport information for H28
  • AirNav airport information for H28
  • FlightAware airport information and live flight tracker
  • SkyVector aeronautical chart for H28