■ My student and I were in the [Runway 5] pattern.… I was instructing my student on patterns and proper procedures. I had heard on the radio two aircraft in the area: Aircraft Y calling a 10-mile final for Runway 5, and I heard Aircraft Z make a takeoff call for Runway 14. The winds at the time were favoring Runway 5. My student and I had already made a previous takeoff and landing on Runway 5 for pattern practice. After I heard the plane taking off Runway 14, I actively…searched for him and could not spot him, so I started to divert my attention to the other aircraft landing on Runway 5. My student started to turn base when Aircraft Y called a 5-mile final behind us. We continued down to the runway and made a safe landing. We came to a full stop on the runway to clean up the airplane and make a very short debrief because Aircraft Y, landing behind us, was on a 1-mile final as he made a radio call. We made a radio call stating that we were departing Runway 5.… I was making sure that my student was doing the proper procedure on takeoff. We were approximately 10 knots below our rotation speed when I looked up and to my left and noticed that there was an aircraft taking off [from] Runway 14…on a direct collision course [with us].

■ I was flying [a small drone] for an infrastructure inspection and training a new pilot to do the same. During the second flight with a different airframe than I usually fly, the trainee mentioned, “Well, it doesn’t have the FAA sticker,” referencing the registration number. I then realized I had forgotten to apply the registration number to the aircraft. The aircraft was registered and therefore had a designated UAS registration number.… I failed to apply it.

■ As Captain, I was the Pilot Monitoring (PM), and the First Officer (FO) was the Pilot Flying for this flight. On the takeoff roll at approximately 90 to 100 knots, I heard the FO make the comment, “There seems to be a lot of airflow through this window.” I glanced over to see…that the window appeared to be closed. I shifted my eyes back to the runway centerline, airspeed, and engine instruments while thinking about what he said. At approximately 110 knots, it became loud with high airflow into the flight deck. The FO shouted, “My window is open.” I quickly glanced over to his side to see he had his left hand on the control wheel and was holding the R2 Flight Deck Window closed by the window lock lever with his right hand.

■ I immediately aborted the takeoff by quickly pulling the throttle to idle and applying full brakes and taking the controls from my student. We started coming to a stop when I announced on the radio that we were aborting the takeoff because of the aircraft departing [Runway] 14. We stopped on the runway and watched Aircraft Z continue their takeoff and…not make any radio calls. Aircraft Y, I believed now on the ground,…made an ‘on the go’ call and departed the area to the south. Aircraft Z departed the area, and we continued our lesson with no further incident.

After the flight, the pilot of Aircraft Y contacted me…to fill each other in. I could tell by the sound of his voice that my aborting the takeoff and his subsequent go-around really shook him up. We talked on the phone about each other’s perspectives, and he said that because of… Aircraft Z [departing 14] and my aborted takeoff, that on his go-around, he almost stalled the airplane and crashed behind or into our aircraft. He was going to stay in the pattern behind us, but decided to go back to his airport after the event.

This event…may have been prevented in a couple of ways. Aircraft Z…should have been listening to the radio and should…not have taken off.… They could have waited until both aircraft were safely out of the way and back into the air before departing the runway.… I may have missed the radio call by…Aircraft Z. Maybe I should have stopped talking and listened. Aircraft Y also could have given me a bit more time to assess my situation and given my student and me some more time to take off again.

■ Upon this realization, I landed the aircraft, and we grounded that aircraft until the registration number had been applied, finishing our inspections for the day with an aircraft which had an adhered registration number. Contributing to this error was the fact that I had been flying two different airframes for the prior three days, and with three days in the field, I was beginning to experience some fatigue. Additionally, high temperatures and humidity were contributing to fatigue. When it came time to fly the aircraft described in this incident, I did not catch the fact that the aircraft’s registration number was not adhered during pre-flight. I also realized that our pre-launch checklist did not have an item in it to check for an adhered registration. To prevent the incident from occurring again, I need to ensure that we add a checklist item for the adhered registration and be doubly careful when flying an airframe that I have not been flying regularly. As always, I need to be looking out for the effects of fatigue and ensure continued vigilance when encountering them.

■ I immediately took the controls.… We were approximately 120 knots, just prior to V1 (129). I took a quick glance at my FO and back to my instruments.… We were Vr + 8 to 9 knots. I then rotated, saw a positive rate of climb, and shouted, “Gear up.” The FO assumed PM [duties] and raised the landing gear. I shouted, “Can you crank the window closed at all?” He responded, “No, it won’t close.” At this point, Tower advised us to contact Departure. I selected the center autopilot, VNAV, and Heading Select with a heading of 360 as assigned. I opened the speed window and remained at flaps 5 to prevent the airplane from accelerating. The faster we would go, the louder the flight deck would be, and the more the FO would struggle to hold the window in position. The FO shouted, “I can’t hear anything from ATC.” … I contacted Departure and informed them that we needed to stop the climb and return to the airport because we had a flight deck window open. We were given a left heading of 270 and told to maintain 4,000 feet. We performed the After Takeoff checklist. My FO stated, “I can’t hear anything from ATC. What do you need from me?” I responded, “ATC is giving us vectors back for the ILS Runway XX. If you can, get flight deck performance for Runway XX and set us up for the ILS.” … Once we were set up and briefings and checklists were completed, I advised ATC we were ready for the approach. Since I was flying while doing the radios myself, and the FO had only one free hand available, I decided…not…to be heads down and message Dispatch through ACARS.… The priority was to fly the plane and get us safely on the ground.… We [requested priority with] two souls…and approximately four and a half hours of fuel on board. ATC asked the nature of the [situation] and I replied, “We have a flight [deck] window cracked.” I meant to say, “cracked open,” however, the noise from the airflow was a little distracting. ATC gave us an intercept heading of 100 and cleared us for the approach.… A normal landing was made at approximately 265,000 pounds.… If I could have done one thing over, I would have shouted, “My controls” in a louder voice. I didn’t take into consideration that the FO could not hear well at that point. I’m also appreciative of our Company training video made by Boeing of a flight with the flight deck window opened. I’m glad that it was shown…during my 767-upgrade training. I never thought I would be in that situation, but thankfully, I had some idea of what to expect. The plane will be extremely loud and distracting, but it will safely fly.