During the preparations for the Pointblank Offensive, the USAAF asked the RAF to consider how to carry out daytime bombing with Spitfire escorts. Fighter Command claimed this was impossible, making several highly questionable calculations to "prove" this. This led to two Spitfires being shipped to Wright-Patterson where many new fuel tanks were added without major effects on performance. Their now excellent range was demonstrated by flying them back across the Atlantic to England. In spite of this demonstration, Fighter Command was slow to consider such adaptations and was not until well after Pointblank was concluded that final sign-off was given, at which point they saw no need for such conversions.