A method of displaying information on a display device of an aircraft, comprising: storing pre-calculated estimated time of arrival minimum data and ETA maximum data in a datastore; displaying a trajectory of a flight path along which the aircraft flies; receiving data at a computer module indicating a particular point selected by a user from the trajectory of the flight path along which the aircraft flies and upon which there is a waypoint related to a time constrained operation, the particular point being any point along the flight path; (a) receiving, by the computer module, user inputs including a required time of arrival target time, a waypoint distance offset, and an RTA tolerance value; (b) retrieving, by a data manager module based on the user inputs, from the datastore ETA minimum data, ETA maximum data and an optimal RTA value that is pre-calculated for a given point on the flight path that is near or associated with the particular point; (c) interpolating, by the data manager module, the ETA minimum data and the ETA maximum data based on the RTA tolerance value and the waypoint distance offset to generate an ETA minimum, an ETA maximum and an optimal RTA for the particular point; (d) displaying in a dialogue box associated with the trajectory of the flight path the ETA minimum and the ETA maximum for the particular point; and (e) repeating steps (a) to (d) until a decision based on the ETA minimum and the ETA maximum is communicated by the user to air traffic control (ATCo) in response to a clearance request therefrom to comply with clearance for the time constrained operation. storing pre-calculated estimated time of arrival minimum data and ETA maximum data in a datastore; displaying a trajectory of a flight path along which the aircraft flies; receiving data at a computer module indicating a particular point selected by a user from the trajectory of the flight path along which the aircraft flies and upon which there is a waypoint related to a time constrained operation, the particular point being any point along the flight path; (a) receiving, by the computer module, user inputs including a required time of arrival target time, a waypoint distance offset, and an RTA tolerance value; (b) retrieving, by a data manager module based on the user inputs, from the datastore ETA minimum data, ETA maximum data and an optimal RTA value that is pre-calculated for a given point on the flight path that is near or associated with the particular point; (c) interpolating, by the data manager module, the ETA minimum data and the ETA maximum data based on the RTA tolerance value and the waypoint distance offset to generate an ETA minimum, an ETA maximum and an optimal RTA for the particular point; (d) displaying in a dialogue box associated with the trajectory of the flight path the ETA minimum and the ETA maximum for the particular point; and (e) repeating steps (a) to (d) until a decision based on the ETA minimum and the ETA maximum is communicated by the user to air traffic control (ATCo) in response to a clearance request therefrom to comply with clearance for the time constrained operation. (a) receiving, by the computer module, user inputs including a required time of arrival target time, a waypoint distance offset, and an RTA tolerance value; (b) retrieving, by a data manager module based on the user inputs, from the datastore ETA minimum data, ETA maximum data and an optimal RTA value that is pre-calculated for a given point on the flight path that is near or associated with the particular point; (c) interpolating, by the data manager module, the ETA minimum data and the ETA maximum data based on the RTA tolerance value and the waypoint distance offset to generate an ETA minimum, an ETA maximum and an optimal RTA for the particular point; (d) displaying in a dialogue box associated with the trajectory of the flight path the ETA minimum and the ETA maximum for the particular point; and (e) repeating steps (a) to (d) until a decision based on the ETA minimum and the ETA maximum is communicated by the user to air traffic control (ATCo) in response to a clearance request therefrom to comply with clearance for the time constrained operation.