My Talk will be Brief because Mr. Kean has covered the field extensively and extremely well.

What is Interchange? Mr. Kean indicated that it is not a very satisfactory description of what takes place because it is not a word which describes it accurately, and I think a good deal of confusion about interchange exists in the minds of many laymen because, unlike most air transport words which had their roots in surface transport, interchange so far as I know is peculiar to air transport; hence people are apt to think that it is something special, and that special rules must apply to it. In fact I suggest that it is nothing of the kind; all it is is a certain kind of charter, and the same rules apply to interchange of aircraft as to any other kind of charter, and the reason that it has been singled out as a special problem for lawyers is that its characteristics make it extremely difficult to work satisfactorily, internationally particularly, if the normal rules are applied.