In the District of Columbia anyone of any age can be prescribed marijuana by a doctor licensed to do so. However, marijuana is only prescribed for extremely debilitating conditions. In most cases a caregiver needs to be issued who is over the age of 18 and registered to dispense and help with administration of marijuana. Each caregiver can only have one patient.
The legal age to purchase/possess marijuana in the District is 21. To get a medical marijuana card you must consult a prescribing doctor and present him with a valid medical reason for him or her to write you a prescription.
No, you are not allowed to take a flight with marijuana in the state of Deleware. It is against the law to board a plane with contraband such as marijuana. I would not reccomend trying to board a plane with illegal drugs of any sort in the state of Deleware.