The flag of the Commonwealth of Massachusetts displays, on both sides, the state coat of arms centered on a white field. The shield depicts an Algonquian Native American with bow and arrow; the arrow is pointed downward, signifying peace. A white star with five points appears next to the figure's head, signifying Massachusetts' admission as the sixth U.S. state. A blue ribbon surrounds the shield, bearing the state motto Ense Petit Placidam, Sub Libertate Quietem ("By the Sword We Seek Peace, But Peace Only Under Liberty"). Above the shield is the state military crest: the bent arm holding a broadsword aloft. The sword has its blade up, to remind that it was through the American Revolution that liberty was won.
The state flag was officially adopted in 1901, but had been used unofficially since the American Revolution of the ensign of the Massachusetts State Navy. In 1971 the earlier pine tree was replaced by the current design.
In April 1776, the Massachusetts Navy adopted the Pine Tree Flag as its naval ensign, consisting of a white field charged with a green pine tree and the motto "An Appeal to Heaven." In 1971 the motto was removed, and the flag was designated "the naval and maritime flag of the Commonwealth". Massachusetts is one of only three states with its own maritime ensign (the other two are Maine and Texas).
My version of a design by Hans. Colors and symbolism from state seal and coat of arms dating from 1780. Down-facing arrow represents peace. Blue on the right side of the flag is for Massachusetts Bay to the east. Posted by Preston Knapp 
MA Flag Proposal "apollohawkridge 1"
MA Flag Proposal "apollohawridge 2"
MA Flag Proposal "apollohawkridge 3"
MA Flag Proposal "apollohawkridge 4"
Proposal "star tree 1" for a flag for the state of Massachusetts, combining the colors and star from the state shield with the tree from the naval ensign. By Qaz Dec 2019 (details)
Proposal "star tree 2" for a flag for the state of Massachusetts, combining the colors and star from the state shield with the tree from the naval ensign. By Qaz Dec 2019 (details)
Proposal "star tree 3" for a flag for the state of Massachusetts, combining the colors and star from the state shield with the tree from the naval ensign. By Qaz Dec 2019 (details)
Part of series of designs for state flags, all in blue and white. (Posted by Ken Morton)
Cranberry, blue, and green are state colors; tree from naval ensign and New England flag; shield and white background from current flag; horizontal stripes represent MA's general shape; blue can be seen to represent the Atlantic Ocean and the state's many water bodies.
Results sheet from the January 2020 contest. 414 designs studied and the winner was the variant flag of New England.
Inspired somewhat from Vexillasny's design. in this case, blue, green, and cranberry. And to the best of my knowledge, these colors have never been actually used in any official state regalia. In my design, the horizontal stripes represent the pretty much horizontal shape of the state. And I'd probably have to reverse-engineer a reason for the 2-1-2 layout of the stripes and prolly think of something for that star as well.
Pine tree taken from the flag of N.E. and "Appeal to Heaven" flag, green for the Worcester Hills, Pioneer Valley, and Berkshires, blue for Massachusetts and Buzzard Bays