This is seriously how my brain works:
I was sitting here writing and thinking of those plastic champagne "glasses" you get at some wedding receptions to toast the bride and groom.
Then I was like...what are they called cuz they aren't flutes...???
So then...I went to look it up and learned this:
The champagne coupe or champagne saucer is a shallow, broad-bowled, stemmed glass, commonly used at wedding receptions, often stacked in layers to build a champagne tower. Champagne is continuously poured into the top glass, trickling down to fill every glass below. Legend has it the shape of the glass was modeled on the breast of Marie Antoinette, Joséphine de Beauharnais, Madame de Pompadour, or one of several other French aristocrats, although this is almost certainly false. The glass was designed especially for champagne in England in 1663, preceding those aristocrats by almost a century.
The coupe came into fashion in the 1930s. It was popularized in post-prohibition America at the Stork Club, where champagne flowed freely and celebrities had bottles of champagne sent to their tables, compliments of the house. The coupe was the champagne glass of choice through the 1960s.
The broad surface area allows champagne to lose its carbonation more quickly, making it less suitable for the current style of very dry champagnes, compared to the sweeter champagnes that were popular in the 1930s, and therefore fell out of fashion except for traditional occasions such as weddings. The coupe is now more commonly used for certain cocktails such as daiquiris.
And I'm nowhere near finished with this restaurant scene. You know...the one where they had champagne. *sigh*