Flutes are popular because they display tiny, rising bubbles perfectly. However, a little air space at the top of the glass does not help flavors develop sufficiently.
The coupe was commonly used in the early 20th century, but stunted champagne's natural effervescence.
Much better to use a large specially-designed champagne flute, or even a white wine glass.
Choice of glass is vitally important and can make all the difference in bringing out the singular flavor of superb champagne such as Dom Pérignon, which is made of grapes from 17 Grands Crus and 1 Premier Cru vineyards.