1930s lot of nine items issued by Richfield Oil Co. Complete set of five numbered "Flight Lessons", each slick paper with four pages printed in blue variety not yellow. Three letters include introductory letter to member which is different than previous lot #2964 as it mentions the flight lessons. Two different letters to parents include one standard issue and one a scarce variety addressed to specific person with matching envelope. Letters and lessons are folded as issued. Welcoming letter has moisture marks at top and bottom. Scattered lt. aging. VG overall.