1933, A Century of Progress Zeppelin Flight, 50c green, top sheet margin plate No.21177 block of four, full original gum with minor usual waves, NH, VF, C.v. $300 as four singles, Est. $100-$150 (Image)

1938, Eagle with Shield, 6c dark blue and carmine, vertical pair imperforated horizontally, full OG, trace of hinge mark, F/VF, C.v. $300, Est. $150-$200 (Image)

1973, Progress in Electronics, 11c multicolored, a single with vermilion and olive litho colors omitted, full OG, NH, VF, C.v. $700, Est. $300-$400 (Image)

1983, Summer Olympics, 40c x4 multicolored, top left corner sheet margin plate No.2222 imperforated se-tenant block of four, full OG, NH, VF, C.v. $650, Est. $300-$400 (Image)

1985, Trans-Pacific Air Mail, 44c multicolored, top left corner sheet margin vertical imperforated pair, full OG, NH, VF, C.v. $600, Est. $250-$300 (Image)

1989, 20th UPU Congress, Futuristic Mail Delivery, (45c) multicolored, se- tenant block of four with light blue (engraved) color omitted (country name and denomination), full OG, NH, VF, C.v. $500, Est. $250-$300 (Image)

1991, Harriet Quimby, 50c multicolored, bottom margin vertical pair imperforated horizontally, perfect condition, full OG, NH, VF and scarce, C.v. $900, Est. $400-$500 (Image)

Zeppelin Flights. 1925 (May 8-10), Airship Los Angeles Return Flight cover from San Juan to Lakehurst to Cleveland, franked by Franklin 3c green in vertical imperforated pair, red three-line confirmation cachet, postmarked on reverse, F/VF, Sieger #20W, €250, Est. $130-$160 (Image)

Zeppelin Flights. 1930 (June 3-6), 1st Europe - Pan America Round Flight postcard, delivered on legs Lakehurst-Seville, Seville- Friedrichshafen, franked by Zeppelin stamp of 65c green, red German and violet American confirmation markings, Friedrichshafen ''6.6.30'' arrival, the card returned to US by ship on June 18 (green Zeppelin marking is alongside at the bottom), VF, Sieger #64A, Est. $100-$150 (Image)

Zeppelin Flights. 1933 (October 23-November 2), Century of Progress Flight, three US covers on legs Miami - Chicago, Chicago - Friedrichshafen and Akron (second landing) - Friedrichshafen, each one franked by ''Baby'' Zeppelin 50c green, each one with appropriate markings and arrival ds, mostly VF, Est. $150-$200 (Image)

1919, pre-printed cover from Arkhangelsk to NYC, franked by two Russian definitives of 15k, censorship paper tape and four-line underlined marking in violet, the text reads: ''Intelligence G.N.Q. Northern Russia Exp. Force. Passed by Censor'', minor flaws, still F/VF and scarce, Est. $150- $200 (Image)

1924, Lincoln Memorial, black two-line overprint ''Canal Zone'' on $1 violet brown, top right corner sheet margin block of four, full OG, NH, close to VF, C.v. $1,600 as four singles, Est. $600-$800 (Image)

MINT COLLECTION ON HOME-MADE PAGES: 1904-76, over 450 mint stamps in singles, pairs and blocks, representing postage, air post and back of the book material, strong in early period, numerous shade, perforation and overprint varieties, nice quality overall, full OG with many NH stamps, F/VF, C.v. is about $6,200 without a premium for NH, Est. $2,000-$2,500 (Image)

MAINLY USED COLLECTION ON HOME-MADE PAGES: 1904-76, about 600 mostly used stamps in singles and pairs, representing postage, air post and back of the book issues, starting with US, Panama and Nicaragua basic stamps, which were used for further Canal Zone overprints, some nicely centered items, minor usual flaws mentioned as always for used material, generally F/VF, C.v. is well over $6,000, Est. $1,000-$1,500 (Image)

1879-94, 22 plate proofs, neatly identified on a stockcard, including 1st set on India Paper, four proofs of the 3rd set on wove paper mounted on cards, complete 4th set of small dies on wove paper, occasional flaws possible, still fresh and F/VF, Postal Department Regulations regarding usage of due stamps is included, C.v. $1,621, Est. $400-$600 (Image)

1912 (February 17), Emeryville Race Track Aviation Meet, stationery postcard 1c blue, addressed to Selma, CA, tied by ''Aeroplane Station Oakland Cal. Feb. 17, 1912'' machine ds (flown on the first day of the Meet), fresh and VF, AAMC #16, Est. $200-$300 (Image)

1931 (May-September), North Pole Flights of Wilkins - Ellsworth Trans-Arctic Submarine Expedition, three-country franking cover from New York to Dayton, OH via London, North Pole, Leningrad and New York, bearing Beacon 5c carmine and blue, uprated by GB King George V stamp of 1½p yellow brown and imperforated single of Soviet Ice-Breaker ''Malygin'' 35k green (on reverse), confirmation and other appropriate markings with arrival ds on reverse, VF, Est. $250-$300 (Image)

1931 (June 19), Trans-Atlantic Flight by O. Hillig and H. Hoiriis pre-printed cover, franked by US Red Cross 2c black and red, due to technical difficulties flight was interrupted at Harbor Grace (Newfoundland) and correspondences were delivered by a ship, upon arrival to Denmark uprated by 25ø light blue and postmarked ''3.7.31'' in Copenhagen, VF, only 30 items carried, Est. $150-$200 (Image)

1931 (July 15-19), Justice for Hungary Non-Stop Trans- Atlantic Record Flight by Alexander Magyar and George Endresz, specially printed postcard, franked by 1c green, upon arrival Hungarian postage due of 32f carmine rose was applied, No. 0094 at top left, all appropriate postal and confirmation markings, VF, Mueller #31, 7,500 points, Est. $200-$250 (Image)

1933 (July 24), Balbo Air Squadron Flight, New York- Rome, cover addressed to Germany, franked by five stamps, including three high value definitives, tied by ''New York Varick St. Jul.24'' duplex, violet ''Italian Air Cruise'' confirmation cachet, blue No.2217 at bottom left, Grociera Aerea Rome drop and Wesseling (Köln district) arrival ds, mostly VF, AAMC #1184f, Est. $500- $600 (Image)

1934 (June 27-July 2), Benjamin and Joseph Adamowicz Trans-Atlantic Flight from New York to Warsaw cover with pre-printed flight itinerary, franked by Washington 2c carmine, upon arrival to Warsaw uprated by Polish air post stamp, signed by both brother-pilots at top, Warsaw ''2.VII.34'' arrival ds, VF, Est. $200-$250 (Image)

1895, Webster, 10c dark green, bottom sheet margin with imprint and plate No.62 horizontal strip of three, full OG somewhat disturbed on margin, NH, fine, C.v. $1,000, Est. $250-$300 (Image)

1895, Marshall, $5 dark green, watermark USPS, fresh color and intact perforation, full original slightly disturbed gum, previously hinged, close to VF centering, PF certificate, C.v. $2,000, Est. $400-$500 (Image)

1895, Marshall, $5 dark green, watermark ''USPS'', neat purple Specimen overprint at the top left, no gum, F/VF, C.v. $400, Est. $150-$200 (Image)

1909, Washington, $1 violet brown, a single with bottom margin plate No.4957, full OG, NH, PF certificate graded F/VF 75, C.v. $1,050, Est. $350-$400 (Image)