Family members of the Ethiopian Airlines crash victims expressed disappointment over the projected recertification of Boeing's 737 Max jets sometime August. They believe the planes shouldn't be allowed to fly just yet.

In an interview with CBS News, Nadia Milleron, the mother of Samya Stumo, a 24-year-old passenger who was killed during the Ethiopian Airlines crash in March, said she is worried that the process for recertifying the questioned Boeing 737 Max jets will be rushed.

"How could you possibly finish the required analysis and investigation by August?" she argued. For Milleron, the Federal Aviation Administration (FAA) and investigators should make sure the planes are completely ready to take flight once more.

FAA Acting Administrator Daniel Elwell clarified on Wednesday that the aviation agency will only provide the second certification to Boeing 737 Max jets if investigating bodies are fully convinced the planes in question are safe.

"Once we are convinced absolutely of the safety of return to service, we will do it," Elwell said of the upcoming recertification. While it was previously projected that the planes will most likely receive certification in August, others have doubts.

A joint international panel has been tasked to carry out a probe on how Boeing's now infamous jets were allowed to fly in the first place. Before the Ethiopian Airlines crash, an earlier Lion Air crash in Indonesia already drew the ire of passengers and global regulators.

An audio recording of a November meeting between American Airlines pilots and a Boeing official added fire to the company's long list of problems. The audio revealed that pilots furiously confronted the official almost a month after the Lion Air tragedy.

Industry analysts predicted that the American jet maker's journey towards getting a second certification for its 737 Max models will be longer and more arduous, especially with the release of the recorded meeting.

Company officials faced Congress on Wednesday to respond to questions raised by investigators and lawmakers regarding the faulty Maneuvering Characteristics Augmentation System (MCAS) believed to be connected to the October and March crashes.

CNN reported that Elwell pledged to reap lessons from ongoing investigations and reviews by spectators who want to ensure that the Boeing 737 Max models are safe to fly. The Congress meeting also prompted Elwell to identify the company's mistakes or failures that allowed for errors in the jets' MCAS system.

The FAA has yet to announce when Boeing will be allowed to fly its 737 Max jets again. In the meantime, the formerly popular planes are grounded worldwide.