in state
With great pageantry and ceremonial splendor. The royal couple is traveling in state across the country, with great fanfare expected at each of their destinations.
in state
With pomp and ceremony, as in The foreign leaders were dining in state at the White House. This expression, dating from the late 1600s, also appears in lie in state, said of a dead body ceremoniously exposed to public view before being interred. This latter usage, dating from about 1700, is generally confined to important public figures, as in His Majesty lay in state in the palace.