If you are carrying cremated remains / ashes on a KLM airline then you should be aware that this is there policy:
An urn can be taken as part of hand baggage, or as check-in baggage.
• The urn’s crematorium certificate must be brought and be shown during security check, so the urn will not be opened.
• If taken as part of hand baggage, the urn can measure max. 55 x 25 x 35 cm / 21.5 x 10 x 13.5 in (l x b x h).
• The urn cannot be made of metal (ie: x-rayable, so wood etc is OK)
• The urn must be sealed and wrapped in such a way that other passengers cannot identify it as an urn.
• To request transportation of an urn, please contact the KLM Customer Contact Centre (+44 20 7660 0293) , quoting your booking code, so they will put a note against your file for check-in use etc