I am not sure I understand the question. Are you sure you want to scale the kerning pairs?
Or do you want to scale the whole glyphs, including the sidebearings? Scale it up proportionally first (best via Filter > Transformations > Transform > Scale or, and this really also includes kerning pairs, via File > Font Info > Font > units per Em), then scale down vertically only via the Palette.
THIS is exactly what I was looking for.
My problem was, that when I was scaling with the "Scaling Tool (S)", the metrics were not included. I had to fix them manually. That was not very accurate...
But with the Transformations-Filter, it works.
Thanks for your support! This application really helps me!
I’m not sure why you would want to do that in Glyphs. When you stretch “letters” you aren’t getting a true extended font. You can do it in InDesign or Illustrator by setting character widths and you can compensate for kerning changes by using Adobe’s Optical Kerning. Creating a stretched font in Glyphs (or any font editor) for a one-off job seems like a lot of work when there are other easier and faster methods available.
I’m not criticizing or commenting about what you are doing, I’m just curious about why you decided to follow this route.