The term 'boat or plane' can be summarized as a VESSEL, which is a 6 letter word. A VESSEL is a type of watercraft or aircraft used for transportation, recreation, or other purposes. Boats and planes are the two most common types of vessels, and they are used for a variety of activities such as fishing, sailing, and air travel. Boats are typically smaller than planes and are powered by an engine or oars, while planes are powered by jet engines and fly through the air. Both boats and planes are important modes of transportation and recreation, and they are essential to many industries.