If it’s what I’m thinking it was Aero. I’ve only seen them in dollar stores around here but I’m pretty sure that that’s what this OP was talking about.
It’s not a food, but I miss banana flavored milk.
I hate white milk, the only way I enjoy drinking it is if it’s flavored with something.
I have a whack of Aero bars. Mom and Canadian Sue send me shipments of chocolate from Canada.
You’re not crazy, I remember it too. It was called 1-2-3 Jello, and it had to be whipped up in a blender to make the layers. I LOVED that stuff. About six years back I found a small cache of it in a BigLots and stocked up. The packaging was labeled in Japanese, IIRC, but it still tasted the same. Yummy!
I also miss Pudding Pops–why don’t they make those anymore? And finally–I don’t remember what they were called but they were soft-serve icecream treats you could buy in the supermarket. The were paper cones with a plastic top and you squeezed them to make the ice-cream swirl out of star-shaped hole on the top. Those were always gone the same day mom brought a box home. 
In britain you used to be able to get milk in a can. It had an unusual taste (unlike somewhere between pasturized ans sterilized milk) but I loved it.
I think caramacks no longer exist either. I liked them too.
Another vote for Space Food Sticks.
I actually thought I’d be the only one to mention them.
A ray of hope for those lost childhood favorites of the 1970’s
Golden Nuggets returned to UK shops in 1999, I do so hope they are still available.
Smooshed Shredded Wheat:
Take two Shredded Wheat bales and place them on a plate
Pour boiling water on them
Smoosh them between two plates, draining the water off.
Butter and sugar.
OHMYGOD…I could live on this.
I LIVED on those things my senior year of high school (1987/88). I was your typical can’t-drag-my-lazy-ass-out-of-bed teenager, so every morning I got up with about 7 minutes left in which to get ready to go to school. So I’d take a Speed Shower (how do I make a Trademark symbol?) and grab 3 Carnation Breakfast Bars and 4 Handi-Snacks (this was back when there was only one variety of Handi-Snacks) on my way out the door. Breakfast was 1 Breakfast Bar and 1 Handi-Snack, and then lunch was 2 Breakfast Bars and 3 Handi-Snacks, plus a milk from the cafeteria. (My mom gave me lunch money but I horded it all week to spend on ill-gotten hooch on the weekend. Ah - the good old days when 5 dollars was enough money to keep me happy for the whole weekend).
When I was younger they also had Carnation Breakfast Squares, which were really yummy, but really dry & a bit powdery under the chocolate coating, so you really needed a glass of milk with them, or you’d expire from the Carnation equivalent of Dunkin’hackin’
Another vote of Pudding Pops, too. Chocolate-Vanilla swirl. I loved that thin coating of ice that was always on the outside, that you had to bite through to get to the creamy goodness inside.
Ooooo, I remember Buc Wheats too. I loved that cereal so much – maybe just because that was the only sweetened cereal my parents would buy us. Back in the early '90s I found something similar with Wheaties Honey Gold, but the flakes weren’t as thick and crunchy. I think those are gone, too, anyway.
One food I remember loving as a kid was something we called “eggdrops”: some kind of grains that looked like fat couscous, but with a darker brown color. They had a nutty flavor and a slightly chewy texture. I can’t find anything similar through Googling, and I don’t know any brand names. Does anybody know what the heck I’m talking about? I miss that stuff.
I remember practically living on Carnation breakfast bars, too – and was away for a while, and then when I was able to get them again, YES! They had been changed.
No idea if this is someone nostalgic trying to recreate the original ones, but I found this recipe:
http://www.budget101.com/recipes/id487.htm
Perhaps someone adventurous could whip up a batch and report back? I liked the ones with the wee chocolate chips, and I don’t remember them having any peanut taste to them…as someone who needs small meals to counteract low blood sugar throughout the day, crikey, I would love CBBs back!
Havarti cheese. REAL Havarti cheese, not the crap they sell in grocery stores labeled “Havarti,” which tastes almost exactly like Jack cheese.
Real Havarti should stink. It should be slightly dry around the edges, but be moist in the middle. It should be riddled with tiny holes. It should be tangy and pungent and delicious.
Anyway. My Dad, who is German, used to buy it at this little Bavarian market in Seattle, before it closed years ago. We haven’t been able to find any nearly as good since, and I miss it lots. Thinly-sliced havarti on hot toast is divine at breakfast.
Kraft American Style Spaghetti - had a kind of cheese sauce. Yummy.
Jello Whip ‘n’ Chill, especially chocolate - a poor man’s mousse
Fizzies - best when licked. To hell with putting them in water.
Jack Frosted - made a sort of milkshake when sprayed into milk. They had packaging problems, though, so sometimes it just oozed out. Also, it was expensive and a can didn’t go far. Wonder why it failed?
Smucker’s Cinnamon Apple Jelly - I can’t believe nobody else has started making this stuff.
Morton Ice Cream Cakes - I don’t know what the real name was. The white cake was delicious, though.
I just finished a bag of Tato Skins, so you can find them.
They are not distributed by Keebler anymore, though. It looks like Poore Brothers bought them out. They list a website, http://www.poorebrothers.com, that seems to indicate that they also produce the TGI Fridays version, so maybe those are the same. But anyway, they’re still out there.
I also miss O’Boisies. I can remember how salty they were. Must’ve had 2000% of your sodium allowance.
Oh yeah, and General Mills Sugar Jets. Greatest cereal ever made. No nutritional value whatsoever. If you take the fruit flavoring out of Froot Loops, and make it spherical instead of doughnut-shaped, that’s what you’d have. I’m working on a process.
And I remain insanely jealous. Those things are ambrosia.
Another vote for the Carnation Breakfast Bars and the O’boises potato chips.
I also liked this candy that came with 2 or 3 fruit flavored powders and candy sticks that looked like giant pills that you would lick then stick in the powder. Can’t remember what it was called (Lick’em stix??)
Another vote here for the space food sticks, though just the chocolate ones. The peanut butter ones were gross.
And I too remember the 1-2-3 Jello. My dad used to buy the red variety - can’t remember now if it was strawberry or cherry.
I miss something more recent - Lay’s Bistro Chips, the applewood BBQ and smoked cheddar flavor. I almost cried when the guy who runs our snack bar here at work told me that they were being discontinued. Probably just as well though - I could eat a whole bag of those at one sitting without even trying.
I used to love those cakes from the Easy Bake Oven. I know they’re still around, but trying to explain why at 28 I have an Easy Bake Oven to my husband or anyone else wouldn’t be fun.
Ooh, and Grippos BBQ chips. They make 'em in Ohio & Indiana, but I live in Missouri now so I can’t get them unless I ask my mom to bring some when she visits.
Other guilty pleasures from childhood: those milkshakes you had to microwave, hot dog buns with chocolate chips poked into them (one of my culinary specialties for breakfast), and Happy Joe’s pizza (minus the really loud siren they’d set off if they found out if was your birthday - that thing used to make me cry).