Lowell Mather

Played by Thomas Haden Church, Lowell is a dim-witted mechanic/handyman who works at the airport. He is a "free agent" of sorts, on the payroll of both Sandpiper and its rival airline Aeromass, as well as anyone else willing to pay him for repairs. He claims that, while he is not an orphan, his brother is. He was married to a woman named Bunny with whom he had several children, but they divorced when Lowell learned that Bunny was sleeping around.

After Brian sank the houseboat Lowell lived on, Lowell lived with Joe and Brian for a time, where he revealed a surprising talent for cooking. After about a year, however, his eccentricities became unbearable to the Hacketts, and they kicked him out to find his own place, which coincided with the conclusion of the insurance investigation, allowing the payout to buy himself a house on land.

Eventually, Lowell is forced to leave Nantucket and enter the Witness Protection Program after witnessing a mob hit. Although it is hard for him to leave the people he has known all his life, Lowell decides he would rather go into hiding than let a guilty man go free to possibly kill again.

Lowell usually wears an orange ballcap, although he is sometimes seen without it at times when it is rude to wear hats indoors. During a later season, Lowell's orange hat goes missing. From then on he wears a red hat in its place. When Lowell leaves Nantucket, he gives the red hat to Joe and Brian to remember him by. The brothers nail the hat to the wall of the hangar in memoriam.