Wow, is that a computer or a prop from an old science fiction movie? In 1975 when this ad was published, computers were fairly uncommon. The travel industry was one of the first to utilize computers for booking and tracking reservations. Sometimes though, I wonder if those same computers are still in use today by the airlines and car rental companies, but I digress.
For those of you not old enough to remember, Don Rickles was one of the most popular comedians of his day. Rickles, affectionately known as "Mr. Warmth", was considered an insult comic, due to his offensive and insensitive stage personality, although by today's standards, he'd be considered fairly tame.
National is touting their Green Lite service here. While green is still National's color, it's now called the Emerald Club. One cool feature of being in the Emerald Club is the Emerald Aisle. Sounds like something out of the game CandyLand, but Emerald Aisle is a section of the car lot where you can go and choose any vehicle you like, assuming you've booked a midsize car or higher. After all, emerald green works for National, but you wouldn't want to show up for your next business meeting in an emerald green car. Now you can thankfully avoid the fashion police assuming you choose wisely!