Ah, where to begin.

>>Creams are not essential for a 12 h flight.<<

It's not just the flight, it's wherever you are travelling to which might not be a place conducive to replacing said medications if they are lost or stolen and accounting for any delays in travel.

As a practicing physician for 15+ years, I would really love to know the evidence-based studies to support that statement.

>>At least not a large tube.<<

Some creams only come in a large tube, and transferring from one container to another invites contamination and possible infection.

>>medications" are better transported in carry-on<<

Absolutely 100% correct.

>>creams are not that difficult to replace<<

Some topicals are very expensive and hard to get in certain areas. Please don't make sweeping generalizations about medications.

Bottom line, always hand carry your medications with the prescription labels visible and having a physician note is always an excellent back up. Your doctor can give you more information on specific issues related to your prescriptions and general health care needs.