Locked in a bitter legislative battle, package delivery giants FedEx and United Parcel Service this summer decided the way to woo lawmakers was to ramp up their lobbying budgets.

From July through September, UPS shelled out $4.4 million to influence federal lawmakers, a whopping $3 million increase from the previous three-month period. FedEx, meanwhile, doled out $5.6 million on lobbying during the same period, up almost $2 million from the prior quarter.

The frenzied summer activity, which included a letter-writing campaign by UPS to Congress, catapulted both companies into the ranks of the biggest spenders on lobbying, according to a review of third-quarter lobbying reports that were due to be filed with Congress on Tuesday.

The latest disclosures underscore that despite the weak economy and President Barack Obama’s barring of lobbyists from working in the executive branch, many of the nation’s key industries and other interests continue to open their wallets in an effort to shape major and minor legislation.

Driving much of the activity is the ambitious Congressional agenda that includes potential reforms of the health care system, proposed regulation of financial companies, union organizing and climate change legislation as well as traditional fights over lucrative defense projects.

Steve Ellis, vice president of Taxpayers for Common Sense, a fiscal watchdog group, said that even though lobbyists are not in favor with the White House, “their love affair still burns bright with Congress.—

Ellis said many companies are willing to spend money to nab a piece of the growing federal budget.

The deadline for filing the disclosure forms was midnight Tuesday. But many large industries and associations had already filed their disclosure forms earlier in the day.

The U.S. Chamber of Commerce, which has historically led in lobbying expenditures, continued to do so, spending a record $34.7 million for the quarter. The business group, which has opposed the administration in such areas as health care, climate change and financial regulation, dramatically upped its spending over the summer. It spent $7.4 million in the second quarter .

The National Association of Manufacturers, which often works with the chamber, also opened its wallet for lobbying by spending $5.7 million in the quarter, compared with $1 million during the spring period.

Another group that significantly raised its lobbying budget was the American Beverage Association, with reported spending of $7.3 million in the third quarter, compared with $1.2 million in the previous period.

The beverage association was fighting a proposed soda tax that had been floated, but has not been adopted, as a way to pay the tab for health care reform. On its lobbying disclosure, the association called the proposed fee “unfair taxes.—

“It just reflects the situation we found ourselves in,— said Kevin Keane, senior vice president of public affairs for the association. He said much of the additional lobbying went toward TV ads.

The Pharmaceutical Research and Manufacturers of America, which has been a key player in the health care debate, also was among the top spenders, shelling out $6.8 million in the third quarter, up slightly from $6.1 million in the previous period.

Close behind was the nation’s largest senior citizens group, AARP, which is also keenly interested in health care reform. It spent $5.7 million, up from $5.3 million the previous quarter.

“Clearly health care has been a huge issue and is the reason for a lot of ramped-up efforts on our part,— said David Certner, legislative policy director for AARP.

He added that while the seniors organization did not hire more people, the staff was spending more of its time on lobbying. Certner also said that the AARP had reduced its lobbying early in the year because of the poor economy.

Another group with a vested interest in health care, the American Medical Association, spent $4 million in the third quarter on lobbying, about the same as it spent in the previous three months.

Aerospace and defense giants that are vying for federal contracts also joined the club of high-dollar lobbyists.

Boeing Co. reported spending $3.7 million, up from $2.8 million in the second quarter. Northrup Grumman Corp. spent $3.6 million, up from $3.5 million in the second quarter. Another defense giant, Lockheed Martin Corp., spent slightly less — $3.1 million in the third quarter, compared with its $3.2 million expenditure in the previous three months.

The top spenders also included those in the energy sector, particularly oil companies that have opposed the climate change legislation being debated in Congress.

The American Petroleum Institute, which represents oil companies, spent $2.2 million in the third quarter on lobbying, up from $1.8 million in the prior three months.

“The spending would reflect the attention on the climate bill,— API spokeswoman Karen Matusic said. She said some of the lobbying funds helped defray the cost of rallies around the country organized by the institute to protest the climate bill approved by the House.

Oil giant ConocoPhillips reported spending nearly $4 million on lobbying for the quarter, an increase of about $700,000 over the previous period.

While the real estate market remains in a slump, the National Association of Realtors still reported spending $4.2 million on lobbying from July through September, up from $3.8 million in the second quarter.

Even the beleaguered American auto industry continued to lobby, although at lower levels. General Motors Co. spent $1.54 million in the third quarter, down from $2.8 million in the second quarter. Chrysler Group spent $823,000 in the third quarter compared with $1 million in the second quarter.

Some of the lobbying was driven by more parochial concerns, such as the effort by UPS to force competitor FedEx to comply with the same rules regarding the unionization of its work force.

UPS has a unionized work force in part because it is regulated by the National Labor Relations Act. The company, arguing that it wanted to level the playing field, successfully lobbied the House to include a provision in the Federal Aviation Administration reauthorization bill that would put FedEx under the NLRA’s jurisdiction. FedEx is currently regulated by the Railway Labor Act.

UPS spokesman Malcolm Berkley said much of the company’s increased lobbying budget was attributed to a letter-writing campaign to Congress.

While the House approved the FAA bill with the union provision in it, the Senate has not included that measure in its FAA reauthorization legislation.

FedEx launched an aggressive lobbying campaign of its own in June aimed at both Washington and outside-the-Beltway audiences. The company has responded that the legislation would increase costs and reduce the reliability of shipments.

The fight between the two companies has been acrimonious and public. When asked about the jump in UPS lobbying expenditures, FedEx spokesman Maury Lane said: “That’s how sick it is. They have paid their employees to write letters.—

Legislation in Congress that would make it easier for workers to unionize has not only preoccupied unions but galvanized conservative groups that were less active during the Bush administration.

The National Right to Work Committee, which has opposed union legislation, reported spending $1.53 million in the third quarter, more than it spent in all of 2008, according to disclosure reports.

Committee Vice President Doug Stafford said that because of pro-union organization efforts in Congress, the Right to Work Committee had shifted more resources to lobbying. With the Democratic-controlled Congress and the Obama administration more predisposed to push union legislation, Stafford said, “we have to be more out there than we have been.—