Difficult to use, poor UX. For example, when entering in a travel companion on the Personal Data section, I enter in the exact alphanumeric number for my companion's MileagePlus account. I am unable to save the information and there is a warning icon with no context next to the MileagePlus number. I can only imagine they've designed this field to accept only numeric values. Therefore, due to Lufthansa's design of this form, there is no way to properly input other frequent flyer program account details and it is absolutely unusable. This has been an ongoing problem with their apps - no concern for other programs.