Martin Burnham, who was killed June 7 after 376 days of captivity in the Philippines, was passionate about his vocation as a missionary pilot, say family and friends. He was a gifted pilot and mechanic, they say, but his real gift was encouraging fellow missionaries.

His love for aviation began in his home region of Wichita, Kansas, known as the "air capital of the world." But Doug Burnham says his brother set his career course in 1970, when their parents began serving as New Tribes missionaries in the Philippines. Martin was 10 years old at the time. "On our first ride in the plane, Martin said, 'I'm going to be a missionary pilot when I grow up,' " he recalls.

The Burnhams' reputation as gifted missionaries began when Martin and his wife, Gracia, arrived in Mindanao in the mid-1980s to restart a defunct flight program for New Tribes Mission. Many local missionaries were bickering with one another and with New Tribes, and many refused to use the flight program.

"Martin and Gracia worked hard to restore a lot of the hurt feelings and confidence," Doug Burnham, also a former New Tribes missionary in the Philippines, told Christianity Today. "They were missionaries to missionaries in many ways—not that they didn't have a ministry among the Filipino people."

The Burnhams' willingness to go the extra mile was even evident among their captors. "They served them with anything they could do for them," Doug Burnham says, recounting conversations with Gracia. "When they would get a package of food sent in to them. … they would share what food they could." Martin was required to porter supplies but never complained, even after numerous slips and falls. He even repaired a satellite phone used by his captors.

Less than a week before his ...