Deferring deliveries of aircraft that Boeing claims are 13.5% less efficient than the MAX is smart business. If you are going to spend the money on new replacement aircraft it seems plausible that taking delivery of an airframe that is up to 13.5% more efficient is the smarter play. How long will the -300's hang in there without becoming a convertible is the real question here. If we have another depressurization event I can only assume the the variant using the skin joints that failed will surely be grounded. Where can we replace that lift after we defer deliveries and toss the 717?