Please be aware that if it is the airline’s fault for a delay, such as overbooking, mechanical issue, or a pilot oversleeping, your insurer is unlikely to cover it. In this case, you should seek compensation from your airline.  On the contrary, if the airline is not at fault in the case of bad weather, natural disaster, or a strike, your claim would generally be covered (as long as it is not a known event at the time of purchase). Therefore, other than the documents that outline the causes of your expenses (e.g., medical reports or a letter from the airline informing you about a delay), you will only need the original and amended travel plans with the terms and conditions or fare rules and the price of these arrangements.