International Virtual Aviation Organisation VZW (IVAO) is a non-profit association which operates a free-of-charge online flight-simulation network.

[5] IVAO, with more than 250,000 registered members, is one of the largest online flight simulation networks that allow users to act as either a virtual pilot or air traffic controller.

All pilots and ATC thereby interact on a dedicated, one-world server environment that simulates world-wide air traffic on an "as real as it gets" basis.

While the largest part of IVAO's active membership is based in Europe, new divisions are continually being created to spread the network coverage world-wide.

IVAO logs all flight and controlling hours and offers its members to obtain virtual pilot and ATC ranks by undergoing training and passing theoretical and practical exams based around real-world aviation regulations and procedures.

Using these programs, SATCO (now VATSIM) was the first large network to create an online air traffic simulation environment.

On December 16, 1998, IVAO was founded when a group of people left SATCO to form a new network after management conflicts developed within the organisation.

[17] In February 2021, a global password reset was issued to all users due to an "unauthorised use of privileged access to IVAO web systems" which led to a security breach that affected its staff members.

[23] January 2022 saw the release of the first quarter objectives for 2022,[24] in the form of a software roadmap to tackle the issues seen during Crowded Skies event of 2021.

Servers weren't able to handle the already expected large number of connections, crashing multiple times, creating a very bad image on the network stability.

[38] The use of a non-textual ATIS will significantly enhance the simulation for IVAO pilots, and controllers, and adds the next-level feature to the Voice 2.0 project.