Sentence:  From International Airport in Los Angeles to International Airport in Houston , as the great four-jet Boeing 707 flies , <WSD>is</WSD> a routine five hours and 25 minutes , including stopovers at Phoenix , El Paso , and San Antonio . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)