Thank you Chris, you are most welcome for trying and basically nailing it, except for #4. Here are the answers.
1. Douglas and later McDonnell Douglas for more versions.
2. A-4, originally A4D.
3. Skyhawk.
4. Because of its small size, it did not require folding wings for aircraft carrier duty, unusual for US Navy carrier aircraft.
Conceived by Douglas's brilliant designer Ed Heinemann in 1952 as the smallest aircraft designed to carry a nuclear weapon on a one-way mission if a third world war was declared, the Skyhawk was in production for 30 years starting with pre-production models in 1954. His design came in at HALF the specified weight,
yet met or exceeded all US Navy requirements. Production A-4s' wingspans were just over 26 feet to 28 feet overall. (The Piper Cherokee 140s I learned to fly in had 30 foot wingspans, for comparison). The Skyhawk was designed also as a jet powered replacement for the Douglas AD-1 Skyraider, also known as the "Spad."
The A-4 "Heinemann's Hotrod" or "Bantam Bomber" was known by Navy pilots as the "Scooter" for the way it took off from carrier decks. I've also heard it called the "Tinkertoy" by USN maintenance personnel. After the Vought A-7 Corsair II replaced it on Navy decks, it was used by US Marine Corps pilots, who, by the way, are considered Naval aviators. The A-4 was also exported to many foreign friendly countries, some operating from land bases. The New Zealand model was the A-4K, for example, now all retired with no military fighter/attack aircraft. Two seat versions of the Skyhawk were built and even a tanker version with two huge wing-hung tanks was produced. The Singapore version was unique with having two separate canopies, the rear one behind and above the forward canopy. Many jet engine changes and upgrades kept the A-4 competitive. Final versions were the Skyhawk II and Super Skyhawk. They had a more bulged canopy for improved visibility.
Are these quizzes still of general interest?