an apple
The airport code for Yakima Air Terminal is YKM.
No, it is not. The nearest international airport to Yakima (in the US) is Seattle-Tacoma International Airport - Seattle, WA (SEA / KSEA). It is about 150 driving miles from Yakima, WA.
The the closest airport is Yakima Air Terminal (IATA: YKM, ICAO: KYKM)
This type of identification signifies what airport this is and where that airport is located. The FAA LID 40G airport identifier refers to Valle Airport in Valle, Arizona.
PIK
The "K" is to identify that it is an airport located in the United States.
That is the airport's IATA Code identifier.
HXD is the airport identifier. (Or KHXD depending what you are using it for.)
A location identifier is the aviation "name" of an airport. For example, Cleveland, Ohio is CLE. When a pilot files a flight plan, he uses identifiers and route numbers of the airways he intends to fly, ending with the destination airport identifier.
It is often referred to as MBJ. The official ICAO identifier is MKJS.
According to Google Maps the distance between Seattle Tacoma International Airport and Yakima WA is 148 Miles (238 kilometers). and the driving time is 2 hours and 31 minutes.
One of the many things that HHH has been used for is, indeed, the regional airport code identifier for the airport at Hilton Head island, South Carolina.