 In first- and business-class cabins, the seat letters for the window seats will typically be the same as in economy, with some letters skipped in between as there are fewer seats per row.For example, if economy cabin is ten across, labeled ABC-DEFG-HJK, the business-class cabin might be labeled AC-DG-HK for a six-across layout, with A-DG-K for a four-across first class.One notable exception to this is Delta Air Lines, which uses sequential letters regardless of cabin layout on all aircraft (AB-CD-EF in business class and ABC-DEF-GHJ in economy).