This has truly been eye opening. I think I need to re-assess just how much standard-classic-cartoon exposure I've had. Does anyone have any suggestions? I am aware of quite a few "classics" but nothing really caught my interest aside from the Rocky and Bullwinkle here.
EDIT: Worth noting I also really like Mr. Magoo (recently discovered it on Hulu)
Its not a bird, plane or frog, but you should check out Underdog (avoid the live action movie, that thing is hot garbage).
Other good cartoons of that era include Mr. Magoo (check out the Christmas Carol special), Loony Tunes (anything prior to the 80s is solid at worst), The Flintstones (some of the spinoffs and TV movies are good, even the first live action movie is good, avoid the second live action movie though), maybe The Jetsons (as long as you accept that there will be no flying cars in the future), Johny Quest (good action/adventure stuff played straight, avoid the 90s CGI/cartoon hybrid), Scooby Doo (anything made before Scrapy Doo was conceived is fun and straight forward enough without taking itself seriously at all), maybe Thundar the Barbarian (mostly for the flavor as it wants to be as good as Johny Quest but just comes off as too camp, but its a good setting none the less), Mighty Mouse, Secret Squirrel and George of the Jungle (the movie's alright, but like Dudley Do-Right, you have to acknowledge that its a different beast from the cartoon).
And for the love of god, check out Wacky Races. I know I recced a bunch of Hanna Barberra stuff above, but this is honestly the single greatest thing they have ever done.
You could also check out things like Speed Racer, Star Blazers and G-Force/Battle of the Planets just to see what Japan was up to with their anime back then.