None of the impact of having your data leaked from your account is in any way modified by using a VPN for your data traffic while you are on the airplane. Hence

None of the impact of having your data leaked from your account is in any way modified by using a VPN for your data traffic while you are on the airplane. Hence the initial reply of that your suggestions of a VPN is irrelevant. Don't try to change this into a "oh but the data leak isn't really that bad of a vulnerability" after having lost that argument.