From the spare room in his apartment in Sydney's inner-west, Adrian Ciaschetti and his business partner David Shepherd can monitor the flight path.
It's a handy piece of real estate that's been transformed into a home office since their app took off in July last year.
"If you've ever booked a flight online, you'll know how frustrating the experience can be," Mr Ciaschetti told SBS.
"It's not very easy to use, things time out and changing flights can be a nightmare [of a] phone call."
Sparrow promises its users a more streamlined experience, letting them book flights in a few swipes on their mobile screens.
Its founders say the aim is to be more efficient than other travel websites like Sky Scanner.
Mr Ciaschetti and Mr Shepherd raised $120,000 from friends and family to get started, putting in half of that amount themselves.
They keep overheads down by outsourcing app development to New Zealand and are yet to pay themselves a wage.
Another investment round is on the cards, but so far the pair say business is going well.
"We've grown 73 per cent of our user base month-on-month and we've grown 123 per cent in revenue month-on-month," Mr Shepherd said.
"But awareness is our biggest challenge, not having advertising dollars [makes it] hard to compete with the bigger players."
Sparrow takes a commission from the airlines and hotels people choose.
There are no additional charges besides the usual airline and credit card fees.
Some of Australia's cheapest airlines aren't offered on the app, with business people and larger groups the main target.
As they take their business into the next phase, the sky seems to be the limit for the young entrepreneurs.
"There's still a lot of functionality we want to build in there, that's a huge part of the growth plan," Mr Shepherd said.
"We'd love to expand overseas and get a bigger team, get an office!"