MPs have raised concerns over flight disruption and heightened fares between London and Scotland.
The cross-party Scottish Affairs Committee has written to airports and airlines over delays and cancellations.
British Airways and EasyJet have also been quizzed over the “stubbornly high” price of flights to Scotland.
The MPs questioned what airports are doing to ensure punctual flights while requesting data on current delays.
They also want more information on how airports are mitigating the impact of staff shortages on flight reliability.
The two airlines have been asked for an assessment of the current situation and for their plans to increase the number of flights connecting Scotland and London.
“Given ticket prices have increased since the pandemic, the MPs ask for airlines’ views on the consequences and long-term sustainability of new higher price points,” the committee said.
The correspondence follows an inquiry by the committee into airport in Scotland, which looked at the impact of the pandemic, local tourism and environmental concerns.
SNP MP and committee chair Pete Wishart said: “Strong connectivity between Scotland and London is not only vital for the Scottish economy, but also necessary for those in Scotland to travel on to destinations all over the world.
“In recent months, our committee has become increasingly concerned with the persistent issues with flights between Scotland and London.
“We have heard evidence of widespread delays and last-minute cancellations.
“Today, we’ve asked airlines and airports to explain why flights have not returned to pre-pandemic levels, with prices stubbornly high and fewer scheduled flights at every airport.”