1883 13 Aug. 2/7 (headline) Style in sky pieces.
1901 G. Ade 121 Her Sky-Piece had a List to the Starboard.
1954 B. Racklin in 28 Feb. (This Week section) 47/1 In the jive vein there is ‘skypiece’ meaning a hat.
2007 A. Theroux xlvii. 780 ‘You like my sky piece?’ He tipped his porkpie hat.