Since its launch in 1986, Ryanair has gone from being a small, private airline to Europe's leading low-cost carrier.

From humble origins plying the Dublin-London route, the airline now flies to destinations all over Europe from hubs in the Republic, Britain, Belgium and Germany.

Credited with lowering the cost of air travel, it made this mode of transport available to a wider Irish public.

But its ascent to the top has not been without controversy.

The airline, under its combative chief executive Michael O'Leary, has crossed swords with many groups in its 16-year history.

Semi-state companies including Aer Lingus and Aer Rianta - and even Bord na Móna in the early days - have been among its chief adversaries.

But other groups have also had run-ins with the airline, which is known for its aggressive cost-control policy.

Its 1997 decision to cut travel agent commissions saw it take on the Irish Travel Agents Association, while the airline's prolonged dispute with baggage handlers over union recognition briefly closed Dublin Airport the following year.

The airline was set up by Cathal, Declan and Shane Ryan, sons of GPA founder Tony Ryan, with an investment of £1 million (€1.27 million) 16 years ago.

Launched as a full-service airline, it quickly ran up losses of £20 million in its early years while going through a number of chief executives.

A Pauline conversion to a "low-fares, no frills" model, based on the example of Southwest Airlines in the US, saved Ryanair and set it on the path to profitability.

It made its first profit of around £300,000 in 1991, the year Mr O'Leary took on the role of chief operating officer. He became chief executive three years later.

After rejecting an approach from Aer Lingus to buy the airline in 1993, Ryanair remained under the control of the Ryan family until 1996 when a consortium led by Texas-based investor David Bonderman bought a 20 per cent stake.

This served as a prelude to the airline's flotation the following year, which raised €148 million (£116.5 million) for the company and the Ryan family.

Since the flotation, the Ryan family have sold €274 million (£216 million) worth of Ryanair shares, while the airline has also made Mr O'Leary a wealthy man.

He retains a little over 7 per cent of the company, while Tony Ryan and his family holds 1.84 per cent as it launches this latest phase of its expansion.