I've found the photo below on SN's
Buy-On-Board menu on their website. The photo shows pieces of what looks like smoked salmon but the description reads 'cream cheese bagel with smoked salmon finished with some cucumber and dill'. Although it is called 'salmon bagel' it is actually 'cream cheese bagel' according to the description. I'm not defending SN and in any case pieces of salmon (if any) were probably smaller than what's shown in this photo.
Did the onboard menu (or any other menu you have seen) include a picture which clearly showed slices rather than pieces of smoked salmon? If you think the photo (or the description you saw) was misleading you might like to contact SN's
company representative. You can also reach them via their Twitter account at
https://twitter.com/FlyingBrussels/.