This is slightly pretentious modern food writing.
On tasting menus these days, a set of (four, six, etc.) small glasses of different varieties of beer presented together gets called "a flight of beer" or "a beer flight." Presumably, the expression has been borrowed to refer to a selection of different and supposedly complementary cookies presented together in an attractive fashion.
(But there is no need for the presentation to involved tiers or levels, such as on gradins.)
From an American restaurant's website:A selection of small portions of a particular type of food or drink, esp. wine, intended to be tasted together for the purpose of comparison. 1978 N.Y. Times 29 Mar. c17/2 There were four flights of wines, as they say in the trade, four spätleses, four ausleses,..[etc.]. 1983 Washington Post (Nexis) 14 Dec. e1 They turned the dinner into a smoked salmon tasting... Each flight of the tasting was garnished differently. 1997 Sydney Morning Herald (Nexis) 17 June (Good Living) 2 An inviting line-up of the famous single malt whiskeys available in tasting flights. 2005 L. L. Narlock & N. Garfinkel Wine Lover's Guide Wine Country 151 The tasting bar offers three to six flights of wine in several categories: classic, prestige, all white, and all red.
Finally, on a wine website, someone wrote the following in answer to the question "Why is a wine flight called a flight?"For those who’ve never ordered a Flight, it’s a sampler we offer of three different beverages (wine, Port or spirits) that you can order to experience a comparative tasting at your table or the bar.
Of course ‘flight of wines’ derived from wine judges who could not agree on which group of wines were worth more than $100 but they eventually agreed that the concept of such wine values was a flight of fancy so they jokingly referred to the wines as a ‘flight of fancy wines’ which for professional reasons was reduced to ‘flight of wines’.