QantasLink announced its bases in Canberra, Hobart and Mildura will shut from April 2026 soon after Rex fell into voluntary administration and budget airline Bonza collapsed.
Executives from the flying kangaroo's regional operation will on Friday front a Senate inquiry examining the reliability and affordability of aviation services in rural Australia.
A submission from Mildura Rural City Council said its airport was a critical link to regional centres in Victoria, NSW and South Australia.
Passengers were concerned the base closure would limit access to reliable air travel from the town 550km northwest of Melbourne.
"It is a lifeline for our community, underpinning economic activity, health access, education, and social connectivity," the council's submission said.
QantasLink's exit also had the potential to discourage investment in the region, the council warned.
"When confidence in air connectivity erodes, the entire regional economy suffers."
The closures would effect about 70 staff across three bases, including 31 cabin crew.
QantasLink did not initially offer redundancy packages because staff could take up jobs in Sydney, Melbourne or Brisbane, the Flight Attendants' Association of Australia said in its submission.
But many employees had long been living in and around Canberra, Mildura or Hobart, owned their homes, had caring responsibilities or had spouses who ran local businesses.
"The decision ... is a commercial decision by Qantas that carries a profound human cost," the association's statement said.
"It treats loyal, long-serving regional staff as transferable assets, ignoring the complex web of family, economic, and social ties that bind them to their communities."
Staff had since been offered various financial packages, including redundancies and funding to either commute or relocate.
QantasLink chief executive Rachel Yangoyan's statement to the inquiry said Australia was not the only country experiencing challenges with regional airlines.
The cost of running regional services was higher on a per-seat basis than metro routes, with more expensive airport charges, fuel and maintenance costs.
But aircraft upgrades represented hundreds of millions of dollars in investment in the regional fleet, while Qantas operates 102 routes to 62 regional destinations, Ms Yangoyan said.
"This month marks 105 years since Qantas was founded in outback Australia and, while we at times need to make tough decisions, we are as committed as ever to investing in the future of regional Australia."
Representatives from airlines, councils and unions will give evidence to the inquiry at Parliament House in Canberra.