Of course, wishing someone a safe flight is completely acceptable. It comes from a good place and is a nice reminder that you have their safety in mind.
Do pilots say ready for takeoff? There is no specific, defined procedure or phraseology for the pilot. In practice, the pilot will typically say something like “Tower, N123 is ready to go”, “ready at [runway] 25 Left”, “ready for takeoff”, “ready for southeast departure”, etc.
Not much is said, apart from the pilot monitoring calling out a few conditions being met: “Power Set” or “Thrust Set”: The engines have now reached the selected power level (it takes a few seconds for the engines to spool up from idle) “80 knots” or “100 knots”: The aircraft has reached a speed of 80/100 knots.
The pilot-in-command of an aircraft shall have final authority as to the disposition of the aircraft while in command. ICAO Annex 2, par. 2.3. 1, specifically empowers the PIC to override any other regulation in an emergency, and to take the safest course of action at his/her sole discretion.
Moreover, there is a list of words with special meaning on flights. For example, “Roger” meaning “received”; “affirm” meaning “yes”; “approach” meaning “coming to land”, etc. The language of aviation is changing and nowadays following the current spelling alphabet pilots use “Romeo” instead of “Roger”.
Regarding the number of people onboard an aircraft, the term soul was used to count the number of passengers and crew. The word can be traced back to the great sailing ships of the 18th century. Back then, many ships were lost at sea, and the missing dead sailors were called lost souls.
Right before a pilot lands, they will typically make an announcement to the passengers informing them that the plane is beginning its descent and to prepare for landing. They may also give instructions on how to fasten seatbelts or stow away any items that are not allowed during takeoff and landing.
The pilot verbalizes “Airspeed Alive” as a reminder to verify that the airspeed indicator is working. If the airspeed indicator doesn't show an indication that it is working, the pilot would typically abandon the take-off while still on the runway and get it fixed before flying.
The call of positive rate (or climb) is made by the PM as an indication that the aircraft is safely climbing away from the ground. This is confirmed by checking that the altimeter indication is increasing. At this point, it is safe to retract the landing gear.
Pan-Pan, short for “possible assistance needed,” is used to communicate an urgent, but not emergency, situation over VHF radio, in the case of aviation, to air traffic control. Examples could include a recreational pilot getting lost, or perhaps needing to climb to a higher altitude to sort a problem out.