Jeff 
4K
Aerial firefighting operator (not a scheduled airline)
B26
Martin B-26 Marauder (likely the A or B variant for civilian/firefighting adaptation as the \'Tanker 43\')
Identifiable by its large round nose greenhouse for the bombardier, classic twin-engine layout with mid-fuselage nacelles, and its firefighting livery typical of postwar bomber conversions in the US.